Search through all files listed in tags table for match for REGEXP.
Stops when a match is found.
To continue searching for next match, use command M-,.
If FILE-LIST-FORM is non-nil, it should be a form that, when
evaluated, will return a list of file names. The search will be
restricted to these files.
Also see the documentation of the `tags-file-name' variable.
(fn REGEXP &optional FILE-LIST-FORM)