Last modified: 2013-03-02 00:35:27 UTC
Unlike all other pages on the wiki, modules can't be categorised. While I don't know of a good way to solve this, it is a rather annoying oversight. On en.wiktionary we've solved it by categorising the talk page instead, but that is not an ideal solution.
Already fixed in Gerrit change #50143. Note this will be deployed with 1.21wmf11, see https://www.mediawiki.org/wiki/MediaWiki_1.21/Roadmap for the schedule.
I presume that the subpage name can be changed somehow? Wiktionary uses ISO language codes as subpages in a few cases, and we don't want the code "doc" to clash.
Yes, by modifying the MediaWiki:scribunto-doc-subpage-name message.