Yes, that would be "Luna Kirkby <llvm@moonbase.lgbt>"

Ah, that's much cleaner! I hadn't realized the test framework could do that.
I've updated the diff accordingly - your example works perfectly, so I've taken that and ditched the now-unnecessary other test.

How does this look? I've got a 'control' test to demonstrate the diagnostic as a child of ignored-qualifiers, as well as a test to demonstrate this diagnostic can be disabled in isolation.

Copying over the comment I left on D99840 explaining it - my existing change only works because it gets bailed out by further code in TokenAnnotator.cpp.
I think your change still is valuable since it's more correct.

Sure thing - would the suite in /clang/test/SemaCXX/ be the right place to put that?

Looking at this again I think the change is flawed. The InitialToken is taken *after* the enum token, and additionally the invocation of ShouldBreakBeforeBrace is falling through to the return false; case every time. As such the call to addUnwrappedLine() is _always_ skipped. This removes the newline for both the Attach and Break styles - but the Break style is then fixed up by some code in TokenAnnotator.cpp that I don't fully understand, which adds the newline back in.

Note also there's significant overlap with the now-committed D99840, though that's missing the change inside ShouldBreakBeforeBrace().
In retrospect I'm a little confused as to why D99840 appears to work without it.

Sorry it took me so long to get back to this - fell off my radar somewhat.
I've updated the release notes, I think it's ready to commit now?
I lack commit rights (first time contributor!) so for attribution it'd be "Luna Kirkby <llvm@moonbase.lgbt>"

Looks like this has been separately addressed by @jroelofs, linking to the updated urls on the Phabricator rather than off-site to GitHub.