[clang] [OpenACC][Docs] Add a release note for Clang 21 (PR #145938)

[Erich Keane via cfe-commits]

erichkeane wrote:

> Hi, I was about to update the Static Analyzer release notes, and I noticed that it had this entry. Could you please move it somewhere more appropriate? I don't think the content right now relates to the Clang Static Analyzer.

WOOOPS!  Thanks for catching this!

https://github.com/llvm/llvm-project/pull/154605

https://github.com/llvm/llvm-project/pull/145938