[clang] [llvm] [Frontend] Add leaf constructs and association to OpenMP/ACC directives (PR #83625)

[Krzysztof Parzyszek via cfe-commits]

kparzysz wrote:

Hey @erichkeane, do you have anything to add?  I have replaced `leafs` in the .td file with `leafConstructs`, and with `leaves` elsewhere.

https://github.com/llvm/llvm-project/pull/83625