[clang] [Clang] Allow diagnostics starting with Arm (PR #98091)

[via cfe-commits]

amilendra wrote:

> This one looks fairly benign, and while I agree that it is good to upstream things wherever possible, my slight objection rests mostly on two principles:
> 
>     * In general the community doesn't take behavior-changing patches purely on the basis of eliminating merge conflicts for code that is out of tree. Things that go upstream need to have a justification that is relevant to upstream.
> 
>     * Changes that land need to come with tests that exercise them.
> 
> 
> FWIW, this particular change looks unlikely to be a source of merge conflicts, as it adds only a single line to a table that is unlikely to be touched very often. I think you'll be okay if this isn't upstream, but I won't complain too loudly if you feel the need to land this anyway.

Thanks for the explanation. Yes, this seems simple enough that it won't be too hard to resolve even if a merge conflict appears. I'll abandon the change. Thanks for taking the time to review this.

https://github.com/llvm/llvm-project/pull/98091