feat: new and awesome grammar, suitable for ST, VSCode, docs and beyond!

Fully covers Tact 1.3.0 🚀

My refactoring kept those goals in mind:

1. Grammar should work with docs, which feature lots of small snippets
without the full context of a regular Tact file

2. Grammar should work with Sublime, VSCode and Monaco editor (VSCode's
underlying editor).

3. Grammar should properly highlight the "happy path", when the
referenced code can be checked by Tact compiler.

After all, this is a TextMate grammar, which operates on sequences of
RegExes. And thus, it's nigh-impossible and mostly pointless to cover
all cases and match up to Ohm's grammer even when one really tries (see
5k+ lines of terse RegEx in TypeScript's TextMate grammar). We just need
the "happy path" to work.

P.S.: Ironically enough, common advice for parsing HTML with regular
expressions is: "Please, don't!", while 80% of all HTML highlighting out
there is done with them :)

Closes #1
Closes #2

.gitignore

@@ -140,3 +140,5 @@ dist
 /.venv
 !.keep
 /*.tact
+/*.ohm
+/*.json