DOC: Adding examples to DataFrameGroupBy.rank #38972 (#42402)
DOC: Adding examples to DataFrameGroupBy.rank #38972 (#42402)

* DOC: Adding examples to DataFrameGroupBy.rank #38972

* DOC: Adding examples to DataFrameGroupBy.rank #38972

* DOC: made the suggested changes

* DOC: changed as suggested

* DOC: changed as suggested

* DOC: updating with black output

* DOC: updating with black output

* DOC: corrected docstring order
pandas-dev/pandas,jorisvandenbossche/pandas,jorisvandenbossche/pandas,dsm054/pandas,rs2/pandas,datapythonista/pandas,rs2/pandas,rs2/pandas,pandas-dev/pandas,dsm054/pandas,jorisvandenbossche/pandas,pandas-dev/pandas,datapythonista/pandas,datapythonista/pandas,rs2/pandas,dsm054/pandas,dsm054/pandas,jorisvandenbossche/pandas,datapythonista/pandas,dsm054/pandas,pandas-dev/pandas