T88660: Emit reflists for <ref> with no explicit <references>
This patch emits a reflist for all ref groups that still have
<ref>s in them at the end of the document. Currently Cite.php only
does so for the default group. See also T88290.
On html2wt the missing <references> are added to the wikitext,
which makes the wikitext correct. Selser catches this if not part
of the edit.
Change tests to include an explicit <references /> tag, and add
one for explcitly testing that they do get added. This last one
has to be blacklisted as the new <references /> don't appear with