Allow setting for link to page whether or not it exists with [[]] format

[kjhf]

currently --search term-- - creates a direct link to the search term, regardless of whether or not the page exists, however the intuitive form is still [[thing]]

today we had a case of a user demonstrating a category that shouldn't exist, e.g. [[Category:$1]], but the bot diligently linked to Category:April 1.

Perhaps this could be customised by namespace (e.g. non-mainspace pages should be always linked, and maybe do the usual search for mainspace?)