Clean up some Chinese installer translations

https://translatewiki.net/wiki/MediaWiki:Mainpagedocfooter/nan was
renamed to MediaWiki:Mainpagedocfooter/nan-latn-pehoeji in July 2024

https://translatewiki.net/wiki/MediaWiki:Mainpagedocfooter/zh-tw was
deleted in July 2023.

For some reason neither of these made it to the repo. Apply them.

(Found doing a codesearch for meta.wikimedia.org for
https://www.mediawiki.org/wiki/Project:MediaWiki_documentation_on_Meta-Wiki)

Change-Id: I84867640a3229fedbebacd936658104453b85d15