[clang] [clang] Fix alias declaration fix-it location for token-split '>>' (PR #184555)

[via cfe-commits]

luoliwoshang wrote:

> This change needs a release note. Please add an entry to `clang/docs/ReleaseNotes.rst` in the section the most adapted to the change, and referencing any Github issue this change fixes. Thanks!

Added a release note entry in clang/docs/ReleaseNotes.rst under "Improvements to Clang's diagnostics", referencing #GH184425.

https://github.com/llvm/llvm-project/pull/184555