[llvm] [llvm-objdump] Support --mcpu=help/--mattr=help without -d (PR #165661)

[James Henderson via llvm-commits]

================
@@ -85,7 +92,7 @@ Members:
   - Name: 'foo.c'
     Size: '1'
 
-## We report an error when the archive is malformed.
+## We report an error when we encounter unexpected an error while iterating files in an archive.
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jh7370 wrote:

```suggestion
## We report an error when we encounter an unexpected error while iterating files in an archive.
```

https://github.com/llvm/llvm-project/pull/165661