Fix: allow reserved words as property identifiers after optional chaining

[rbonestell]

Summary

Fixes #377.

Reserved words (delete, class, return, etc.) are correctly treated as property_identifier nodes after . but produce ERROR nodes after ?. (optional chaining). This is because the reserved('properties', ...) context is not propagated through the ?. token path — likely a tree-sitter core issue.

This PR works around it by explicitly listing all reserved words as valid alternatives in the member_expression property field via a new _keyword_identifier rule.

Additionally, this PR fixes JSX parsing of reserved/contextual keywords as tag names, attribute names, and member expression properties (a pre-existing issue). Credit to @SegaraRai for identifying and implementing the JSX fix (commit).

Before:

a?.delete(b);  →  ERROR
a?.class;      →  ERROR
a?.return;     →  ERROR
<class />      →  ERROR
<Foo.class />  →  ERROR
<a class="v"/> →  ERROR

After:

a?.delete(b);  →  (call_expression (member_expression … (optional_chain) (property_identifier)) (arguments …))
a?.class;      →  (member_expression … (optional_chain) (property_identifier))
a?.return;     →  (member_expression … (optional_chain) (property_identifier))
<class />      →  (jsx_self_closing_element (identifier))
<Foo.class />  →  (jsx_self_closing_element (member_expression (identifier) (property_identifier)))
<a class="v"/> →  (jsx_self_closing_element (identifier) (jsx_attribute (property_identifier) (string …)))

Changes

• grammar.js: Extract RESERVED_WORDS and CONTEXTUAL_KEYWORDS as shared constants to eliminate duplication across reserved.global, _reserved_identifier, and the new _keyword_identifier rule. Add _keyword_identifier (inlined) to the member_expression property field alongside $.identifier inside the existing reserved('properties', ...) wrapper. Add jsx_keyword_identifier and jsx_member_expression rules to support reserved words in JSX contexts.
• test/corpus/expressions.txt: Add test case for optional chaining with reserved words.
• test/corpus/jsx_identifiers.txt: Add test cases for JSX reserved word identifiers (contributed by @SegaraRai).
• package.json: Add tree-sitter to devDependencies (required by bindings/node/binding_test.js).
• .github/workflows/ci.yml: Pin node-version: 22 for Node binding tests (tree-sitter@0.25.0 cannot compile with Node 24).
• src/: Regenerated via tree-sitter generate.

Acknowledgments

Thanks to @SegaraRai for testing this branch and contributing the JSX reserved word fix (#378 comment).

Notes

• All 118 corpus tests pass on all platforms.
• The reserved('properties', ...) wrapper is retained for the . path and forward compatibility — when tree-sitter core fixes the propagation issue, the explicit alternatives become redundant but harmless.
• The JSX fix introduces a dedicated jsx_member_expression rule (separate from nested_identifier) so that _jsx_identifier (which includes reserved words) is used for property resolution in JSX member expressions like <Foo.class />.

[SegaraRai]

Thanks for putting this together. I tested this branch locally and noticed a follow-up issue on the JSX side:
reserved/contextual keywords no longer parse correctly as JSX tag and attribute names.

For example, cases like these no longer parse correctly in JSX:

• <class />
• <svg:true />
• <Foo.class />
• <a class="v" for="x" const="y" await="z" />

I put together a small follow-up fix on top of your branch here:
SegaraRai@e6d6e42

Please feel free to reuse or cherry-pick that commit if it is useful. I validated this locally against the affected JSX corpus cases, but I did not run the full CI matrix.