Backport #15213
`enry.IsVendor` is kinda slow as it simply iterates across all regexps.
This PR ajdusts the regexps to combine them to make this process a
little quicker.
Related #15143
Signed-off-by: Andrew Thornton <art27@cantab.net>
Move langauge detection to separate module to be more reusable
Add option to disable vendored file exclusion from file search
Allways show all language stats for search
