Add bracket forms

[savq]

• Rename _top_level to _block_form.
  • Top level was never a very accurate name.
• Add _bracket_form.
  • Many rules already had a pattern like choice(expression, closed_assignment).
• Remove let_binding and do_parameter_list.
  • let and do use lists of _bracket_form now.
• Remove argument_list, and use tuple_expression instead.
  • Julia doesn't distinguish between the two. In most places (x) is a parenthesized expression, but in signatures it's a tuple. Giving a greater dynamic precedence to parentheses solves this problem (same as in lezer-julia).
  • This causes a regression in test performance?
• Remove named_argument and named_field.
  • Any = inside brackets is parsed as _closed_assignment now.
• Allow _block_form in const_statement.
  • Closes bug: error parsing const struct fields #163
• Refactor macro_identifier and _scoped_identifier.
  • _scoped_identifier is only used in import paths and inside macro identifiers, so it makes sense to just hide it. If @Foo.bar ever becomes illegal syntax, then we can just remove it.
  • Use an alias to fake the field expression in scoped macrocalls better (Foo.@bar).
  • See Unify scoped_identifier and field_expression #74
• Replace _comprehension_clause with generator
  • Place the _bracket_form inside the generator, instead of having the comprehension clause as a sibling in the parse tree.

Note for editors:

• Any query that uses named_field, named_argument or let_binding can use assignment instead.

Notes for semgrep:

• Since there's no pattern/expression distinction, parsing everything in function parameters, let bindings and do bindings the same way is easier than having separate rules for each. In all cases we need to extract a "pattern" from a _bracket_form.

[savq]

Hi @amaanq, I'm getting a failure on test_can_load_grammar. I thought this was a bindings issue, but updating the bindings (running tree-sitter version 0.25.0) didn't seem to work. Do you know what might be the issue here?

(Running the tests locally also works fine)

EDIT: Generating with 0.24 works fine, so I'm keeping that version.