This fixes serveral shortcomings of the current implementation:
- valid recipt definitions eg
foo bar="quz":
where previously interrupted by justfile/double_string
and therefore they where not highlighted correctly
- global variable assignments where not captured at all
This commit allows using the <semicolon> expansion in commands, instead
of `\;`.
It makes commands look more elegant, and prevents new-comers from
falling into the trap of using <a-;> without escaping the semicolon.
