"I wouldn't object to stylizing the API code to bring it in line with
the rest of MW on principle, but I'm not gonna bother myself." --Roan
<http://www.mediawiki.org/wiki/Special:Code/MediaWiki/60657#c5108>
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* Instead of hiding read-restricted modules, throw an error when a user without read rights tries to use them
* Do the same for write modules when $wgEnableWriteAPI is false
* Indicate whether a module needs read or write rights in action=help and action=paraminfo
* BREAKING CHANGE: action=purge now requires write rights and, for anonymous users, a POST request
