Requests for comment/Improve search

We should improve search.

Potential improvements

 * Make search user interface suck less
 * T103637 – Consider auto-completing of "insource:" and other magic prefixes when using search inputs (perhaps similar to Gerrit)
 * Reactivate cross-wiki search across Wikimedia wikis
 * T109957 – Restore cross-wiki (interwiki) search across all public Wikimedia wikis
 * Add regex support to intitle
 * T115683 – Add a command-line option to mwgrep to allow it to search a particular page across all wikis
 * T12808 – Introduce Special:Suffixindex
 * Make search indices more accessible and usable
 * T109715 – Replicate production elasticsearch indices to labs
 * Kill mwgrep (needs task?)
 * T71489 – Expose mwgrep functionality on-wiki
 * T88247 – insource should search article text on non-wikitext pages. Probably.