Improve module name handling for local custom code (#40809)
* Improve module name handling for local custom code
* Use `%lazy` in logging messages
* Revert "Use `%lazy` in logging messages"
This reverts commit 5848755d5805e67177c5218f351c0ac852df9340.
* Add notes for sanitization rule in docstring
* Remove too many underscores
* Update src/transformers/dynamic_module_utils.py
* Update src/transformers/dynamic_module_utils.py
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Co-authored-by: Matt <Rocketknight1@users.noreply.github.com>