Function: regex_escape

--Usage--
> regex_escape(some_string)

Escape a string so it can safely be used in a [[type:regex|regular expression]].
The regular expression will match the literal string, and nothing else.

--Parameters--
! Parameter	Type			Description
| @input@	[[type:string]]		String to escape.

--Examples--
> regex_escape("some(thing)") == "some\\(thing\\)"