First export with https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1033888
[v] Verify autonym correctness in language-data
[v] Add to `includes/languages/data/Names.php`
[v] Add to RELEASE-NOTES
[v] Set fallback if needed
-- [v] In core (`languages/messages/Messages*.php`)
-- [v] In jquery.i18n (`src/jquery.i18n.fallbacks.js`)
-- [v] Remove fallback gender aliases if needed
[v] Add namespace translations
-- [v] Add gender aliases if needed
-- [v] Check that namespace translations don't conflict with language codes
[v] Add $linkTrail
[v] Add date formats (if needed)
[v] Add digit conversion (if needed)
[v] Define wider line-height in `resources/src/mediawiki.skinning/i18n-headings.less` (if needed)
[ ] Remove the language from Wikibase and WikibaseLexeme if needed
[v] Remove from translatewiki after deploying the core change
-- [v] `mw-config/LanguageSettings.php`
-- [v] `mw-config/FallbackSettings.php`
[ ] Test language search in UniversalLanguageSelector and fix the search index if needed