[wp-docs] Default connection info now in templates

[mrmist]

Okay so the last edit of "Editing wp-config.php" finally pushed me over 
the edge.  It just seems that no matter how many warnings are splashed 
all over the page, some folk will still try to put their real connection 
information into the Codex page.

So, in a final effort to stop folk doing so, I've abstracted all the 
connection info bits into templates, so it's at least a step removed.

That'll fox 'em.
-- 
mrmist