Update HTMLFastPathParser::scanTagName() to return an ElementName instead of a Span<CharType>.
Pull request: https://github.com/WebKit/WebKit/pull/12270
Committed 262484@main (8e6de7844cbb): <https://commits.webkit.org/262484@main> Reviewed commits have been landed. Closing PR #12270 and removing active labels.
<rdar://problem/107513839>