Verify Parsoid link support works for us, then see if we can remove WikiLinkFixer.
We might need to start tracking HTML versions, since old HTML still needs to be fixed. Also, we need to request https://www.mediawiki.org/wiki/Specs/HTML/1.5.0 or later (currently 1.2.1).
For the relative path issue, we could start using BaseHrefFixer for all content.