Added labels, functions for CMD/BAT files
Merge branch 'patch-4' of github.com:XVilka/highlight.js into dos
Attributing Anton Kochkov (@xvilka) as a contributor.
Tidied up DOS comments.

- renamed COMMENTS → COMMENT
- removed unnecessary .concat()
- require \b after @rem
Reset keyword relevance in DOS.
Merged DOS envvar definition into a single regex.