Extract repeated pattern into wiki_append_pre_start()
Extract repeated pattern into wiki_append_pre_start()

This refactoring will make it easier to add code to handle CSS classes
in PRE_START tags (for syntax highlighting).

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

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