[clang] [llvm] [AArch64] Add ability to list extensions enabled for a target (PR #95805)

[David Spickett via llvm-commits]

DavidSpickett wrote:

Also please list the impact, if any, on `--print-supported-extensions` in the commit message. I think it got a column with the FEAT_ names added, which is a nice improvement.

https://github.com/llvm/llvm-project/pull/95805