replace_8bit_linear modules_to_not_convert default value fix

[BlackSamorez]

What does this PR do?

Fixes the default value of modules_to_not_convert of utils.bitsandbytes.replace_8bit_linear.

Before submitting

• [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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• [ ] Was this discussed/approved via a Github issue or the forum? Please add a link to it if that's the case.
• [x] Did you make sure to update the documentation with your changes? Here are the documentation guidelines, and here are tips on formatting docstrings.
• [ ] Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag members/contributors who may be interested in your PR.

@younesbelkada

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.