fix(semantic/jsdoc): handle even-numbered backtick sequences in JSDoc parsing

[Boshen]

Summary

Fixes #19137.

• The JSDoc parser only handled odd-numbered backtick sequences (1, 3, 5, ...) for toggling in/out of code sections. Double backticks ( ``) used in CommonMark to escape backticks inside inline code were silently ignored, causing the parser to stay in "code mode" and miss all subsequent @tags.
• Replace the boolean in_backticks flag with a backtick_count tracker that records the opening sequence length and only closes when an equal-length closing sequence is found, matching CommonMark semantics.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes a bug in the JSDoc parser where even-numbered backtick sequences (especially double backticks ) were not properly handled, causing the parser to remain in "code mode" and miss subsequent @tags``. The fix replaces a boolean flag with a counter that tracks the opening backtick sequence length and only closes when an equal-length sequence is encountered, matching CommonMark semantics.

Changes:

• Replaced boolean in_backticks flag with backtick_count: u32 to track opening backtick sequence length
• Implemented CommonMark-compliant backtick matching where opening and closing sequences must have equal counts
• Added regression test for double-backtick handling with nested code fence

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
crates/oxc_semantic/src/jsdoc/parser/parse.rs	Replaced boolean backtick flag with counter-based matching logic for CommonMark compliance
crates/oxc_semantic/src/jsdoc/parser/jsdoc.rs	Added regression test for issue #19137 with double backticks and code fence

[codspeed-hq]

Merging this PR will not alter performance

✅ 47 untouched benchmarks
⏩ 3 skipped benchmarks¹

---

_{Comparing fix/jsdoc-double-backticks (ca41b4c) with main (655c38f)}

Footnotes

1. 3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[Boshen]

Merge activity

• Feb 24, 6:51 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Feb 24, 7:00 AM UTC: Boshen added this pull request to the Graphite merge queue.
• Feb 24, 7:14 AM UTC: Merged by the Graphite merge queue.