Drop AttributeName alias and use AttributeNames namespace instead. This is more consistent with what we do for ElementNames and looks nicer for attributes in namespaces (such as XML::langAttr).
Pull request: https://github.com/WebKit/WebKit/pull/12745
Committed 262974@main (91443cf6c069): <https://commits.webkit.org/262974@main> Reviewed commits have been landed. Closing PR #12745 and removing active labels.
<rdar://problem/108054649>