[clang] [clang][analyzer] Add more notes to PointerSubChecker (PR #102432)

[Balázs Kéri via cfe-commits]

balazske wrote:

If the `ArrayBoundsV2` checker is finished it should find all of the cases in the test of `PointerSubChecker` that have out-of-bound indexing, and including the cases where a single variable is handled like an 1-element array? If yes the bounds check is not needed in this checker, only the check for different memory object. I like it better if the bounds check is then removed before the PointerSub checker goes out of alpha (this means now). If the bounds check is removed this checker will not report the cases where invalid indexing occurs because that is a different error.

https://github.com/llvm/llvm-project/pull/102432