Fix crazy hyperlinks in taxonomy-version pages.
Fix crazy hyperlinks in taxonomy-version pages.

These pages used a combination of bare URLs and Markdown links, which
made for unpredictable results in our final HTML. The new logic is
simpler and assumes that any hyperlinks have proper Markdown braces (and
absolute URLs) so that they'll render and work properly.

OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree,OpenTreeOfLife/opentree