[llvm] [DebugInfo] Enable deprecation of iterator-insertion methods (PR #102608)

[Stephen Tozer via llvm-commits]

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@@ -60,6 +60,8 @@ class UnaryInstruction : public Instruction {
       : Instruction(Ty, iType, &Op<0>(), 1, IB) {
     Op<0>() = V;
   }
+  LLVM_DEPRECATED("Use BasicBlock::iterators for insertion instead",
+                  "BasicBlock::iterator")
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SLTozer wrote:

I think these (and the other cases in this file where you've added `LLVM_DEPRECATED`) could be replaced with `InsertPosition` arguments - especially the `HANDLE_` cases, where we have 3 different methods for each type, which all forward to the same `InsertPosition` fn underneath. Not sure why I missed these the first time, but (as long as it works) it should probably be done now.

https://github.com/llvm/llvm-project/pull/102608