Parse warnings

I think it would be a good idea to store, somewhere within `ObjDumpAddressMap`, metadata about any issues encountered during parsing. For example, the parser will not include line 4-5 below in the addrMap because, from line 3-5, no filename was established — since the parser only establishes the `FOUND_FILENAME` state if the parsed line contains a single token.

```
1 /usr/include/c++/13/bits/B.h:
2 B.h 398 0x6c4a x
3
4 B.h 402 0x6c5b x
5 B.h 455 0x6c6b x
```

This would require a change to `ObjDumpAddressMap` and `ObjDumpParser`. ObjDumpParser could simply return an extra element called "metadata" and contain the parse warnings. I also think warning codes should be used with an associated message.

Start by reading ObjDumpParser and ObjDumpAddressMap, then trace how the sample lines are handled when no filename has been established. Define how parse warnings and their codes and messages are represented and returned. Done means the affected parsing issues are retained as metadata without losing the existing address map behavior.

Written by the indexing model from the issue text.