Document std::byte pointer scaling fix

Add a minor analysis note for the reduced false positives in suspicious pointer scaling when indexing std::byte buffers.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jketema

cpp/ql/src/change-notes/2026-10-29-suspicious-pointer-scaling-byte.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* The `cpp/suspicious-pointer-scaling` query no longer reports false positives for intentional pointer arithmetic from `std::byte*` buffers.