'parser-grammar-unused-reason' used for a few properties with used parser-grammars. We should use 'parser-grammar-comment' in those cases and ensure 'parser-grammar-unused-reason' isn'
<rdar://problem/103835748>
Pull request: https://github.com/WebKit/WebKit/pull/8148
Committed 258405@main (ebc41da45e84): <https://commits.webkit.org/258405@main> Reviewed commits have been landed. Closing PR #8148 and removing active labels.