Recognize colon-delimited second part of Runas_Spec that specifies
permitted groups, e.g.:
alan ALL = (root, bin : operator, system) ALL
This implementation is sloppy because it accepts any amount of colons
delimiting further Runas_Lists, but for now that's better than bailing
out completely as soon as a colon is encountered (esp. given that the
default sudoers uses these colons, breaking highlighting OOTB).
Also, while at it, make Vim recognize all Tag_Spec items, not just
{,NO}PASSWD
closes: vim/vim#15607bd69b39514
Co-authored-by: Christian Brabandt <cb@256bit.org>
13c739a664
