Reuse link_target if link_text is Qnil in _Wikitext_append_hyperlink
Reuse link_target if link_text is Qnil in _Wikitext_append_hyperlink

This cleans up a few call sites of _Wikitext_append_hyperlink. The
majority of these sites pass in the same text for the link target
and link text parameters, so teach the function to automatically
reuse the link target as the link text if no link text is explicitly
provided.

Signed-off-by: Wincent Colaiuta <c76ac2e9cd86441713c7dfae92c451f3e6d17fdc@wincent.com>

geni/wikitext,wincent/wikitext,geni/wikitext,wincent/wikitext,geni/wikitext,barnaclebarnes/wikitext,barnaclebarnes/wikitext,barnaclebarnes/wikitext