User story: As a non-WMF user of MediaWiki full-text search, I want to be able to configure custom analysis chains that are more appropriate for my use case.
For example: while you can specify $wgLanguageCode = 'cs';, that only allows you to enable the same specific analysis chain as used on cswiki. If we change that analysis on our end, it also changes for external users when they upgrade MediaWiki. If you want to do something different (like using the Czech stemmer + ICU folding), you can't easily do so (it may be possible with lots of hacking and manual maintenance, but that's sub-optimal).
@dcausse & @TJones discussed this some, and @dcausse found a way to inject config to update or replace a language-specific configuration. An example config is done for Czech P13907. This should be documented in our on-wiki docs.
- Update appropriate documentation page(s) on-wiki with general method for doing this, and at least one specific example. Should be reviewed by another search developer.