TYPING: keywords in df.sort_values and sr.sort_values cannot be annotated

[charlesdong1991]

Observed in the PR #30402 and PR #27237

Annotation seems not to be able to added for sort_values. If added, error message will pop up in CI:

pandas/core/series.py:2691: error: Signature of "sort_values" incompatible with supertype "NDFrame"
pandas/core/frame.py:4701: error: Signature of "sort_values" incompatible with supertype "NDFrame"

[jbrockmendel]

To make the signatures match, by would need to be added to Series.sort_values

[jacobaustin123]

by would need to be added to Series.sort_values (as the first argument, so API breaking) and we would need to remove the default by=None argument in NDFrame.sort_values in generic.py.

[jbrockmendel]

These now have types, though there is a "type: ignore" on the DataFrame method. Closable?