DOC: methods available only for `SeriesGroupBy` objects

[kwhkim]

Pandas version checks

• I have checked that the issue still exists on the latest versions of the docs on main here

Location of the documentation

https://pandas.pydata.org/docs/reference/groupby.html

Documentation problem

SeriesGroupBy.nunique is included in the table methods available only for SeriesGroupBy objects but it is also include in the table methods available in both SeriesGroupBy and DataFrameGroupBy. It is also true of .value_counts()

Suggested fix for documentation

Delete .value_counts() and .nunique() from the table methods available only for SeriesGroupBy` objects

[TarunRKaushik]

take