Add tests that simulate the different handling of whitespace-only text
items between older (< v2.9.359) and newer PDF.js releases and check
that describing and anchoring selectors works in both cases.

Fix anchoring of text quotes and positions in PDF.js releases (>=
2.9.359) that include https://github.com/mozilla/pdf.js/pull/13257.

The client's anchoring relies on the text content of pages extracted via
PDF.js's text APIs (`PDFPage.getTextContent`) to match the `textContent`
of the hidden text layer element. In older PDF.js releases acheiving
this alignment required excluding text items with all-whitespace text,
because PDF.js did not create elements in the text layer for these. In
PDF.js releases after https://github.com/mozilla/pdf.js/pull/13257 this
filtering is no longer needed.

The fix in this commit is to feature-detect whether the active version
of PDF.js includes this change or not and filter or not filter text
items accordingly.

Future changes to PDF.js could cause mismatches between the result of
`PDFPage.getTextContent` and the rendered text layer in other ways, so a
sanity check has been added which logs a console warning if a mismatch
is detected.

The `checkQuote` helper's code suggested that it was expected to be
passed a range. However it was being called with a string. This happened
to work because the implementation only used the `toString` method,
which exists in both Range objects and strings.

TypeScript 4.4 complained that an indexed property lookup was
unnecessarily checked for truthiness. The check was however necessary.
The index type was wrong. Change the type to be correct and adjust other
code accordingly.

Disable a change/feature added in TypeScript 4.4 so that our existing
code typechecks. In most cases the handler is just making the pretty safe
assumption that the thrown error is a subclass of `Error`.

Fixes typecheck error with TypeScript 4.4.

Bumps [typescript](https://github.com/Microsoft/TypeScript) from 4.3.5 to 4.4.2.
- [Release notes](https://github.com/Microsoft/TypeScript/releases)
- [Commits](https://github.com/Microsoft/TypeScript/compare/v4.3.5...v4.4.2)

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Bumps [axe-core](https://github.com/dequelabs/axe-core) from 4.3.2 to 4.3.3.
- [Release notes](https://github.com/dequelabs/axe-core/releases)
- [Changelog](https://github.com/dequelabs/axe-core/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/dequelabs/axe-core/compare/v4.3.2...v4.3.3)

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Bumps [eslint-plugin-react](https://github.com/yannickcr/eslint-plugin-react) from 7.24.0 to 7.25.1.
- [Release notes](https://github.com/yannickcr/eslint-plugin-react/releases)
- [Changelog](https://github.com/yannickcr/eslint-plugin-react/blob/master/CHANGELOG.md)
- [Commits](https://github.com/yannickcr/eslint-plugin-react/compare/v7.24.0...v7.25.1)

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Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.973.0 to 2.978.0.
- [Release notes](https://github.com/aws/aws-sdk-js/releases)
- [Changelog](https://github.com/aws/aws-sdk-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js/compare/v2.973.0...v2.978.0)

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Bumps [core-js](https://github.com/zloirock/core-js) from 3.16.2 to 3.16.4.
- [Release notes](https://github.com/zloirock/core-js/releases)
- [Changelog](https://github.com/zloirock/core-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/zloirock/core-js/compare/v3.16.2...v3.16.4)

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Bumps [terser](https://github.com/terser/terser) from 5.7.1 to 5.7.2.
- [Release notes](https://github.com/terser/terser/releases)
- [Changelog](https://github.com/terser/terser/blob/master/CHANGELOG.md)
- [Commits](https://github.com/terser/terser/compare/v5.7.1...v5.7.2)

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Bumps [mocha](https://github.com/mochajs/mocha) from 9.1.0 to 9.1.1.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mochajs/mocha/compare/v9.1.0...v9.1.1)

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Bumps [sass](https://github.com/sass/dart-sass) from 1.38.0 to 1.38.2.
- [Release notes](https://github.com/sass/dart-sass/releases)
- [Changelog](https://github.com/sass/dart-sass/blob/main/CHANGELOG.md)
- [Commits](https://github.com/sass/dart-sass/compare/1.38.0...1.38.2)

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Bumps [autoprefixer](https://github.com/postcss/autoprefixer) from 10.3.2 to 10.3.3.
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/autoprefixer/compare/10.3.2...10.3.3)

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Bumps [katex](https://github.com/KaTeX/KaTeX) from 0.13.13 to 0.13.16.
- [Release notes](https://github.com/KaTeX/KaTeX/releases)
- [Changelog](https://github.com/KaTeX/KaTeX/blob/master/CHANGELOG.md)
- [Commits](https://github.com/KaTeX/KaTeX/compare/v0.13.13...v0.13.16)

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Bumps [@actions/core](https://github.com/actions/toolkit/tree/HEAD/packages/core) from 1.4.0 to 1.5.0.
- [Release notes](https://github.com/actions/toolkit/releases)
- [Changelog](https://github.com/actions/toolkit/blob/main/packages/core/RELEASES.md)
- [Commits](https://github.com/actions/toolkit/commits/HEAD/packages/core)

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Bumps [sass](https://github.com/sass/dart-sass) from 1.37.5 to 1.38.0.
- [Release notes](https://github.com/sass/dart-sass/releases)
- [Changelog](https://github.com/sass/dart-sass/blob/main/CHANGELOG.md)
- [Commits](https://github.com/sass/dart-sass/compare/1.37.5...1.38.0)

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Bumps [core-js](https://github.com/zloirock/core-js) from 3.16.1 to 3.16.2.
- [Release notes](https://github.com/zloirock/core-js/releases)
- [Changelog](https://github.com/zloirock/core-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/zloirock/core-js/compare/v3.16.1...v3.16.2)

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  dependency-type: direct:development
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Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.968.0 to 2.973.0.
- [Release notes](https://github.com/aws/aws-sdk-js/releases)
- [Changelog](https://github.com/aws/aws-sdk-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js/compare/v2.968.0...v2.973.0)

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Bumps [mocha](https://github.com/mochajs/mocha) from 9.0.3 to 9.1.0.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mochajs/mocha/compare/v9.0.3...v9.1.0)

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Bumps [autoprefixer](https://github.com/postcss/autoprefixer) from 10.3.1 to 10.3.2.
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/autoprefixer/compare/10.3.1...10.3.2)

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Replace the deprecated `whitelistUrls` config option in Sentry with
`allowUrls`. `whitelistUrls` was deprecated in Sentry v5.18.0.

Also revise the comments to be more succinct and note what happens if an
exception does not have a useful stack trace.

Previously, if the user tried to register a listener called `connect`, it
could lead to problems and result in the channel not be connected.

With this change, we reserve the `connect` name for internal purposes,
and if a user tries to register the `connect` listener it would result
on an error been raised.

Bumps [@hypothesis/frontend-shared](https://github.com/hypothesis/frontend-shared) from 3.6.0 to 3.7.0.
- [Release notes](https://github.com/hypothesis/frontend-shared/releases)
- [Changelog](https://github.com/hypothesis/frontend-shared/blob/main/CHANGELOG.md)
- [Commits](https://github.com/hypothesis/frontend-shared/compare/v3.6.0...v3.7.0)

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Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.963.0 to 2.968.0.
- [Release notes](https://github.com/aws/aws-sdk-js/releases)
- [Changelog](https://github.com/aws/aws-sdk-js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js/compare/v2.963.0...v2.968.0)

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Bumps [@octokit/rest](https://github.com/octokit/rest.js) from 18.9.0 to 18.9.1.
- [Release notes](https://github.com/octokit/rest.js/releases)
- [Commits](https://github.com/octokit/rest.js/compare/v18.9.0...v18.9.1)

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Bumps [dompurify](https://github.com/cure53/DOMPurify) from 2.3.0 to 2.3.1.
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](https://github.com/cure53/DOMPurify/compare/2.3.0...2.3.1)

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Several tests in range-util-test.js started failing locally after the
most recent Puppeteer upgrade with actual and expected values differing
by up to 1.0.

Change the tests to check for approximate equality, which is all that is
required for this use case.

Bumps [path-parse](https://github.com/jbgutierrez/path-parse) from 1.0.6 to 1.0.7.
- [Release notes](https://github.com/jbgutierrez/path-parse/releases)
- [Commits](https://github.com/jbgutierrez/path-parse/commits/v1.0.7)

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Add an explanation of why this function should be used rather than
calling `fetch` directly. The details of thrown errors have been moved into a
`@throws` block.

A pedantic but accurate point was made that "server error" is a response
you'd expect for a 5xx status.

This can enable more helpful error formatting by downstream consumers.

All `fetch` requests from the client now use the `fetchJSON` wrapper and
hence throw the same `FetchError` response if they fail.