DOC: Enforce Numpy Docstring Validation for pandas.DatetimeIndex.to_period (#58440)

* DOC: add RT03 for pandas.DatetimeIndex.to_period

* DOC: remove RT03 for pandas.DatetimeIndex.to_period

* DOC: remove RT03 for pandas.Series.dt.to_period

Author: tuhinsharma121

ci/code_checks.sh

@@ -100,7 +100,6 @@ if [[ -z "$CHECK" || "$CHECK" == "docstrings" ]]; then
         -i "pandas.DataFrame.var PR01,RT03,SA01" \
         -i "pandas.DatetimeIndex.indexer_at_time PR01,RT03" \
         -i "pandas.DatetimeIndex.snap PR01,RT03" \
-        -i "pandas.DatetimeIndex.to_period RT03" \
         -i "pandas.Grouper PR02" \
         -i "pandas.Index PR07" \
         -i "pandas.Index.append PR07,RT03,SA01" \
@@ -242,7 +241,7 @@ if [[ -z "$CHECK" || "$CHECK" == "docstrings" ]]; then
         -i "pandas.Series.dt.round PR01,PR02" \
         -i "pandas.Series.dt.seconds SA01" \
         -i "pandas.Series.dt.strftime PR01,PR02" \
-        -i "pandas.Series.dt.to_period PR01,PR02,RT03" \
+        -i "pandas.Series.dt.to_period PR01,PR02" \
         -i "pandas.Series.dt.total_seconds PR01" \
         -i "pandas.Series.dt.tz_convert PR01,PR02" \
         -i "pandas.Series.dt.tz_localize PR01,PR02" \

pandas/core/arrays/datetimes.py

@@ -1207,6 +1207,7 @@ def to_period(self, freq=None) -> PeriodArray:
         Returns
         -------
         PeriodArray/PeriodIndex
+            Immutable ndarray holding ordinal values at a particular frequency.
 
         Raises
         ------