Use Codex design tokens where possible, and implement custom dark
theming for things for which there is no suitable design token.
This means we're changing the colors for light mode ever so slightly.
We need to style the search panel for dark mode, so we might as well
tackle T371436 and use CSS-only Codex components. The same is done for
the "Go to line" panel (can be opened with Mod+Alt+g). The messages in
this panel are now also localizable.
The search panel (and goto line panel) are abstracted, with helpers to
create the Codex components. These will not only be used here but also
for the upcoming preferences panel (T359498).
Visually, the search and goto panels were inspired by the 2017 editor
and share a similar layout. CodeMirror similarly uses a more compact
design than usual to maximize the real estate of the editor itself.
Other changes:
* Bump codemirror/search to get latest bug fixes
* Remove stylelint ignorance and fix errors
* Move CM5 styles to ext.CodeMirror.less
* Move CM-specific styles out of mediawiki.less and into codemirror.less
* Move WikiEditor-specific styles to codemirror.wikieditor.less
(incidentally, these only apply to CodeMirror 6)
* Correct qqq documentation; the "dialog" should be called a "panel"
* extension.json: alphabetize list of messages
Bug: T365311
Bug: T371436
Bug: T359498
Change-Id: I6a3bbc6bce4e490886753ff484e377c1763de456
