Colorize rest parameters like other formal parameters

[caleb531]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions

Description of the Change

Currently, the tree-sitter grammar does not colorize rest parameters in functions. This is in contrast to the first-mate grammar, which does colorize such parameters. This PR colorizes rest parameters as formal-parameter.identifier, like other function parameters.

Before:

After (with these PR changes):

Current first-mate grammar:

Alternate Designs

The selector was chosen because it is similar to the existing selector for formal parameters, so it should have no conflicts with other grammar rules.

Benefits

Rest parameters are now treated just like other formal function parameters.

Possible Drawbacks

None that I can see, since the grammar rule's selector is limited in scope.

Applicable Issues

N/A

[rsese]

Failure looks unrelated, we restarted it but same error.

[jasonrudolph]

@caleb531: Similar to #652 (comment), I think we may want to use the scope names that the TextMate grammar uses. What do you think?

Scopes assigned using TextMate

Scopes assigned using Tree-sitter grammar on this branch

[caleb531]

@jasonrudolph Done! The scope is now variable.parameter.function.

[jasonrudolph]

Thanks for this, @caleb531! ⚡🙇