* Delete jQuery and underscore.js

* Move underscores.js setup to searchtools.js

* Update jQuery.url(en|de)code

* Update jQuery.getQueryParameters

* Firefox bug is no longer present

xref https://bugzilla.mozilla.org/show_bug.cgi?id=645075#c49

* Update jQuery.fn.highlightText

* Use enum instead of magic number

* Update test descriptions to remove obsolete jQuery reference

* Update Documentation.getCurrentURL

* Revert accidental fix of Documentation.getCurrentURL

* Update Documentation.initOnKeyListeners

* Update Documentation.hideSearchWords

* Update Documentation.highlightSearchWords

* Update Documentation.initDomainIndexTable

* Use arrow functions and const

* Replace $(document).ready

* Strict mode

* Move Documentation.hideSearchWords next to Documentation.highlightSearchWords

* Update translation functions in Documentation

* Replace $(document).ready in searchtools.js

* Update Scorer

* Update Search.hasIndex, Search.deferQuery, Search.stopPulse

* Prefer window.location

* Update Search.init

* Update Search.loadIndex

* Update Search.setIndex

* Update Search.startPulse

* Add _escapeRegExp

* Update Search.makeSearchSummary

* Update Search.htmlToText

* Update Search.performSearch

* Factor out _displayNextItem

* Update Search.query

* Update Search.performObjectSearch

* Update Search.performTermsSearch

* Remove underscores.js setup

* Use Sets

* Update test configuration

* Fix test failures

* Drop unused make/get URL functions

* Strict mode in searchtools.js

* Remove outmoded check for jQuery and underscore.js

* Ran prettier

prettier --print-width 120 --no-semi --quote-props as-needed --no-bracket-spacing --arrow-parens avoid --write sphinx/themes/basic/static

* Remove more references to jQuery and underscore.js

* Remove jQuery and underscore.js licences

* Update classic theme for no jQuery

* Update all other themes for no jQuery

* Restore jQuery & underscores.js to Sphinx themes

Enables a more gradual deprecation

* Added deprecation note to CHANGES

* Run prettier with defaults

* Update deprecation message to include extensions, note that sources must be copied

* oops

* Address Pradyun's feedback

* Forgot this one

* `let` doesn't work, as it is scoped to the block...

* Remove missed jQuery in sphinx13 theme

.. note::

   $ find sphinx tests LICENSE doc/conf.py -type f -exec sed -i '' -e 's/2007\-20../2007-2021/' {} \;
   $ git co sphinx/locale/**/*.js sphinx/templates/epub3/mimetype

In HTML5, <script> elements default to MIME type text/javascript. The
HTML5 living standard and MDN recommend against including the attribute.

From https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-type

> The HTML5 specification urges authors to omit the attribute rather
> than provide a redundant MIME type.

From https://html.spec.whatwg.org/#the-script-element

> Authors should omit the type attribute instead of redundantly setting
> it.