Tree-sitter grammar: support characters

[OceanOak]

Changelog:

Tree-sitter-darklang
- Update the grammar to support characters 

#5321

[StachuDotNet]

One minor change requested.

Also, doesn't need to be part of this PR, but it's worth considering using ".immediate()' more in our grammar. I'm not sure what happens for things like ' a ' right now -- I suspect those spaces are ignored, where they shouldn't be (and this probably applies to other parts of our grammar, like potentially 1 . 2 parsing of floats, etc. Anyway, doesn't need to be addressed in this PR but worth some effort in this space.

[OceanOak]

I'm not sure what happens for things like ' a ' right now -- I suspect those spaces are ignored

Currently, it returns an error, it doesn't ignore the spaces
(ERROR (UNEXPECTED 'a'))

same for 1 . 2

(ERROR (positive_digits) (symbol) (positive_digits)))

Would you expect a different result?

[StachuDotNet]

I'm not sure what happens for things like ' a ' right now -- I suspect those spaces are ignored

Currently, it returns an error, it doesn't ignore the spaces (ERROR (UNEXPECTED 'a'))

same for 1 . 2

(ERROR (positive_digits) (symbol) (positive_digits)))

Would you expect a different result?

No that's great! .immediate() is just a thing that's been in the back of my head as something we might need to look into, but it seems I was overestimating its need in some way. Thanks for looking into it!