HighlightRegister should be renamed to HighlightRegistry
<rdar://problem/116262991>
Pull request: https://github.com/WebKit/WebKit/pull/18531
Committed 268873@main (5c10221be14f): <https://commits.webkit.org/268873@main> Reviewed commits have been landed. Closing PR #18531 and removing active labels.
*** Bug 262417 has been marked as a duplicate of this bug. ***