[clang] [llvm] [mlir] [IR][NFC] Rename insertDbgValueIntrinsic -> insertDbgValue (PR #212151)

[Marc Auberer via cfe-commits]

marcauberer wrote:

>As an aside, I think we could remove DbgInstPtr too at some point (not in this PR), as it's a union that was added to help the transitionary phase between intrinsics and records.

Yes, will do that in a follow-up.

https://github.com/llvm/llvm-project/pull/212151