Doc/59592/fix docstring validation errors (#59611)

* adding extended summary, populating return description and adding see also section

* populating return description section

* populating return description section

* fixing zfil docstrign as per PR #59597

* removing methods whose docstrign has been fixed from code_checks.sh script

---------

Co-authored-by: Matthew Roeschke <[email protected]>

Author: specialkapa

ci/code_checks.sh

@@ -71,7 +71,6 @@ if [[ -z "$CHECK" || "$CHECK" == "docstrings" ]]; then
         -i ES01 `# For now it is ok if docstrings are missing the extended summary` \
         -i "pandas.Series.dt PR01" `# Accessors are implemented as classes, but we do not document the Parameters section` \
         -i "pandas.MultiIndex.reorder_levels RT03,SA01" \
-        -i "pandas.MultiIndex.to_frame RT03" \
         -i "pandas.NA SA01" \
         -i "pandas.NaT SA01" \
         -i "pandas.Period.freq GL08" \
@@ -128,7 +127,6 @@ if [[ -z "$CHECK" || "$CHECK" == "docstrings" ]]; then
         -i "pandas.Timedelta.to_timedelta64 SA01" \
         -i "pandas.Timedelta.total_seconds SA01" \
         -i "pandas.Timedelta.view SA01" \
-        -i "pandas.TimedeltaIndex.as_unit RT03,SA01" \
         -i "pandas.TimedeltaIndex.components SA01" \
         -i "pandas.TimedeltaIndex.microseconds SA01" \
         -i "pandas.TimedeltaIndex.nanoseconds SA01" \

pandas/core/indexes/datetimelike.py

@@ -441,13 +441,25 @@ def as_unit(self, unit: str) -> Self:
         """
         Convert to a dtype with the given unit resolution.
 
+        This method is for converting the dtype of a ``DatetimeIndex`` or
+        ``TimedeltaIndex`` to a new dtype with the given unit
+        resolution/precision.
+
         Parameters
         ----------
         unit : {'s', 'ms', 'us', 'ns'}
 
         Returns
         -------
         same type as self
+            Converted to the specified unit.
+
+        See Also
+        --------
+        Timestamp.as_unit : Convert to the given unit.
+        Timedelta.as_unit : Convert to the given unit.
+        DatetimeIndex.as_unit : Convert to the given unit.
+        TimedeltaIndex.as_unit : Convert to the given unit.
 
         Examples
         --------

pandas/core/indexes/multi.py

@@ -1894,6 +1894,7 @@ def to_frame(
         Returns
         -------
         DataFrame
+            DataFrame representation of the MultiIndex, with levels as columns.
 
         See Also
         --------