[llvm] [llvm][DebugInfo][DWARF] Use formatv() instead of format() (PR #191308)

[Konrad Kleine via llvm-commits]

kwk wrote:

@s-barannikov @DavidSpickett I've split the PR into two PRs: one for DWARF (here) and one for LogicalView and GSYM [over here](https://github.com/llvm/llvm-project/pull/191838/changes). I hope this is good. File naming wise it seemed logical to do the split this way but if you disagree I can always change it.

https://github.com/llvm/llvm-project/pull/191308