Find rects are a list of page/rect pairs, so we can store as PDFPageCoverage.
<rdar://problem/129086490>
Pull request: https://github.com/WebKit/WebKit/pull/29404
Committed 279607@main (7fc80cb809a3): <https://commits.webkit.org/279607@main> Reviewed commits have been landed. Closing PR #29404 and removing active labels.