[llvm] [Verifier] Require that dbg.declare variable is a ptr (PR #134355)

[Stephen Tozer via llvm-commits]

https://github.com/SLTozer commented:

Principle SGTM, probably calls for a documentation update: this could be extremely minor just to stress the "new" requirement, updating the text for `#dbg_declare` in SourceLevelDebugging.rst:'
```
- The first argument is an SSA value corresponding to a variable address, and is
+ The first argument is an SSA `ptr` value corresponding to a variable address, and is
```

https://github.com/llvm/llvm-project/pull/134355