Support `page:{number}` or `page:{start}-{end}` filters in the sidebar.  When
the query is a number, it must match the page label exactly. When it is a range,
it matches the page number if:

 - The start and end of the range, and page number, are all numeric
 - The page number is between the parsed `start` and `end` points,
   inclusive

Part of https://github.com/hypothesis/client/issues/5937.