Fix SS06 formatting errors
Errors resolved (from list in #29254):
pandas.DataFrame.filter
pandas.DataFrame.first
pandas.DataFrame.idxmax
pandas.DataFrame.idxmin
pandas.DataFrame.last
pandas.DataFrame.reindex
pandas.DataFrame.pivot_table
pandas.DataFrame.reorder_levels
pandas.DataFrame.unstack
pandas.DataFrame.melt

Validated with `python scripts/validate_docstrings.py`

Referencing issue: #27977
