Preserve trailing struct comments in generated C (closes #336)

[khushi-infinity]

Summary

Trailing /// comments after the last field of a schema struct were emitted before a later generated type instead of inside the generated C struct. This change keeps those comments with their schema
struct and places them before the generated closing brace.

Changes

• Store trailing documentation comments on the schema struct and clear parser comment state before advancing past }.
• Emit the saved comments inside the generated C struct.
• Add a regression test for multiple trailing comment lines and for a separate comment after the closing brace.

Testing

• cmake -S . -B /private/tmp/flatcc-issue336-build -G "Unix Makefiles" -DFLATCC_CXX_TEST=OFF -DCMAKE_BUILD_TYPE=Debug — passed.
• cmake --build /private/tmp/flatcc-issue336-build --target cgen_test test_generated — passed; generated C compiled.
• ctest --test-dir /private/tmp/flatcc-issue336-build -R cgen_test --output-on-failure — passed, 2/2 tests.
• git diff --check — passed.
• ASan/UBSan build did not complete: Apple Clang treated an existing sprintf deprecation in src/compiler/semantics.c:1536 as an error, so the sanitizer test did not run.
• cppcheck and clang-format were unavailable.

Issue

Fixes #336.

AI assistance

ByteAsk assisted with investigation, implementation, regression-test development, verification, and drafting this description. This text is AI-generated and has not been represented as human-written.

[mikkelfj]

Insufficient AI capability.