Duplicated `TraversableResourcesLoader` and `wrap_spec`

[FFY00]

8207434 seems to have mistakenly added some TraversableResourcesLoader and wrap_spec implementations to the _adapters module. Objects with the same name and better implementation already exist in _compat, and it seems to me these ones are leftover from a previous code redesign. Can you confirm @jaraco?

Waiting on #221 getting resolved to submit a PR as it will conflict.

[jaraco]

I encountered this confusion as well while getting back up-to-speed on this project.

The key difference between the implementation in _adapters and _compat is that _adapters.* is used in CPython 3.10, where the FileReader and ZipReader and NamespaceReaders exist natively for their respective loaders. _compat is used in the backport only and exists to support older Pythons where those loaders don't provide the native implementations presenting TraversableResources.

I can update the docstrings in those modules to reflect this need.

[FFY00]

That clarifies it, thanks!