Remove browserify-shim

Revert "Bump prettier from 1.19.1 to 2.0.1"

This reverts commit 5cb9041d.

Add selectors for direct-linked annotation, group IDs

Bumps [prettier](https://github.com/prettier/prettier) from 1.19.1 to 2.0.1.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/master/CHANGELOG.md)
- [Commits](https://github.com/prettier/prettier/compare/1.19.1...2.0.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bump @sentry/browser from 5.14.2 to 5.15.0

This is obsolete with the current version of the "hammerjs" package.

As a result of evolution of the libraries involved, this build tool is no
longer required.

A minor change was required in one test to adjust to the fact that
Angular now uses jqLite, as it does in the actual application, instead of jQuery.
This is because "jquery" is no longer automatically added to the bundle
when "angular" is added.

Remove "raf" dependency

Bump mocha from 7.1.0 to 7.1.1

Bumps [mocha](https://github.com/mochajs/mocha) from 7.1.0 to 7.1.1.
- [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/v7.1.0...v7.1.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@babel/preset-env](https://github.com/babel/babel) from 7.8.7 to 7.9.0.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/compare/v7.8.7...v7.9.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [eslint-plugin-react-hooks](https://github.com/facebook/react/tree/HEAD/packages/eslint-plugin-react-hooks) from 2.5.0 to 2.5.1.
- [Release notes](https://github.com/facebook/react/releases)
- [Changelog](https://github.com/facebook/react/blob/master/CHANGELOG.md)
- [Commits](https://github.com/facebook/react/commits/HEAD/packages/eslint-plugin-react-hooks)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [aws-sdk](https://github.com/aws/aws-sdk-js) from 2.641.0 to 2.643.0.
- [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/v2.641.0...v2.643.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@babel/preset-react](https://github.com/babel/babel) from 7.8.3 to 7.9.1.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/compare/v7.8.3...v7.9.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@babel/core](https://github.com/babel/babel) from 7.8.7 to 7.9.0.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/compare/v7.8.7...v7.9.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@octokit/rest](https://github.com/octokit/rest.js) from 17.1.0 to 17.1.1.
- [Release notes](https://github.com/octokit/rest.js/releases)
- [Commits](https://github.com/octokit/rest.js/compare/v17.1.0...v17.1.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@sentry/browser](https://github.com/getsentry/sentry-javascript) from 5.14.2 to 5.15.0.
- [Release notes](https://github.com/getsentry/sentry-javascript/releases)
- [Changelog](https://github.com/getsentry/sentry-javascript/blob/master/CHANGELOG.md)
- [Commits](https://github.com/getsentry/sentry-javascript/compare/5.14.2...5.15.0)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Remove feature-flag switch: Render `AnnotationOmega` in all cases

This used to have an effect when we used proxyquire for mocking. It does
nothing now.

requestAnimationFrame is supported natively [1] by all the browsers we
support.

[1] https://caniuse.com/#search=requestanimationframe

Add keyboard navigation to MarkdownEditor to improve a11y

- `arrow left`, `arrow right`, `home` and `end` keys are all supported and modeled after https://www.w3.org/TR/wai-aria-practices/examples/toolbar/toolbar.html

- Add roving tabIndex value for all toolbar elements.

This is a pre-requisite to removing the feature flag

This is part of eliminating direct access to store state, and a tiny
piece of simplifying the `groups` service.

Remove "invisible threads" logic

Remove "extend" dependency

This had been replaced with object spread or `Object.assign` apart from
in one instance.

Tune virtual thread list debouncing

When scrolling through a long list of annotations quickly, the sidebar
could display blank space for a long period of time. This was happening
because the debounced update function waited for a period of at least
20ms with no "scroll" events, and a gap of that length could take some
time to appear if there was a queue of scroll events being delivered.

Fix the issue by adding an upper bound of 100ms after a scroll event before
recalculating the list of visible threads.

Also make sure to cancel any pending updates after the `detach` method
is called.

This used to be required in order to run logic in the `<annotation>`
component that saved new highlights to the server, in the case where the
highlight's annotation card was off-screen. This is no longer required
since that is now handled by the `autosave` service.

Allow tab to submit tag

Run `yarn upgrade` to fix GitHub security alerts

Fix `acorn` security vulnerability warning by upgrading all packages to
current compatible versions using `yarn upgrade`.

After this, I also pruned some unused dependencies by running:

```
rm -rf node_modules
yarn
```

Add keyboard shortcuts for the Annotate/Highlight ("adder") toolbar

 - Add tests for multiple modifier keys

 - Add assertion to a test without any

Trigger an error for incorrect use of `matchShortcut` by throwing an
error if multiple non-modifier keys are specified.