fix: preserve macro adjacency with the C 2 scanner

[exKAZUu]

Why

Comments between a macro name and ( make the macro object-like, while a line splice alone preserves function-like adjacency. C++ inherits the grammar from C and must adopt the C 2.0.0 scanner contract to distinguish these cases. This is the corresponding C++ repair for WillBooster/tree-sitter-c#40.

Requirements

• required: Improve all resolvable issues across the requested grammar repositories, checking existing PRs to prevent duplicates and creating a separate PR for each repair worth addressing.
• required: For each PR, run review-booster, then complete-pr, then release.
• required: Preserve public C++ node names, fields, parameter ranges, ordinary expression parsing and configured query captures.
• chosen: Adopt the released C 2.0.0 grammar and its shared scanner helper rather than duplicate adjacency recognition. Port both macro-name recognition and splice-aware parameter scanning because the macro-name token ends before its lookahead splices.
• chosen: Exercise all four inherited newline splice forms, Unicode and universal-character macro names, pragma extras, recovery outside macro definitions and incremental edits. Keep node types unchanged.
• chosen: Retain inherited unreachable C single-statement rules in the generated grammar description. The C++ switch override remains compound-only as before this macro repair, and the generator omits all 15 inherited single-statement rules from parser.c and node-types.json. Removing them or enabling unbraced C++ switches is not required for macro adjacency; the latter needs a separate statement/query compatibility repair.

Customer Summary

Comments and whitespace keep C++ macros object-like. Line splices alone preserve function-like parameters, including when an editor adds or removes the separating text.

Technical Summary

Pin C 2.0.0, copy its shared preprocessor headers and wire the inherited macro-name external token into the C++ scanner. Consume splice-only separation before the opening parameter parenthesis. Regenerate the parser while retaining the node schema and C++ scanner features.

Testing

Parser generation, Wasm build and bun run verify pass. The macro-adjacency, corpus, inherited-C and query suites pass; the latest main integration also passes all nine macro-adjacency and typeof tests. Regression coverage includes actual configured C/C++ highlight queries. All checks on c2062c4 pass, including platform, examples, performance and robustness coverage.