DOC: Fix some RT02 issues in docstrings

[DeaMariaLeon]

• closes #xxxx (Replace xxxx with the GitHub issue number)
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

Towards #49968

[datapythonista]

Thanks for the clean up @DeaMariaLeon, looks good. Just a minor comment, not sure if it's affecting the execution or not.

[datapythonista]

Suggested change

	pandas.api.extensions.ExtensionArray.unique \
	pandas.api.extensions.ExtensionArray.unique

I think you need to remove the backslash here, since this is the last in the list now

[MarcoGorelli]

thanks for working on this!

looks like there's still some errors:

 Error: /home/runner/work/pandas/pandas/pandas/core/frame.py:4923:RT02:pandas.DataFrame.align:The first line of the Returns section should contain only the type, unless multiple values are being returned
Error: /home/runner/work/pandas/pandas/pandas/core/series.py:4643:RT02:pandas.Series.align:The first line of the Returns section should contain only the type, unless multiple values are being returned
Error: /home/runner/work/pandas/pandas/pandas/core/accessor.py:95:RT02:pandas.Series.dt.total_seconds:The first line of the Returns section should contain only the type, unless multiple values are being returned

[mroeschke]

Thanks @DeaMariaLeon

[DeaMariaLeon]

Thank you!