[llvm] [DebugInfo] Convert format() to formatv() in DWARFVerifier (PR #179194)

[Konrad Kleine via llvm-commits]

kwk wrote:

Does it make sense to replace:

```c++
"DIE has " + AttributeString(Attr) + " with invalid encoding"
```

with

```c++
llvm::formatv("DIE has {0} with invalid encoding", AttributeString(Attr)
```

as well? I think this adds to the readability but for sure this is a NFC and I don't know about common practice.

https://github.com/llvm/llvm-project/pull/179194