[llvm] [llvm][dwarfdump] Pretty-print DW_AT_language_version in non-verbose dwarfdump (PR #164222)

[Orlando Cazalet-Hyams via llvm-commits]

OCHyams wrote:

It looks like `DW_AT_language` prints the pretty string in normal and verbose-mode (e.g. `DW_LANG_C_plus_plus_14`). Not sure what's best, just noting existing behaviour. (I feel like for all these named constants verbose mode should give name + raw number? not sure if others feel the same way.)

https://github.com/llvm/llvm-project/pull/164222