DOC: add RT03 for pandas.interval_range (#58800)

Author: tuhinsharma121

ci/code_checks.sh

@@ -441,7 +441,6 @@ if [[ -z "$CHECK" || "$CHECK" == "docstrings" ]]; then
         -i "pandas.errors.UnsupportedFunctionCall SA01" \
         -i "pandas.errors.ValueLabelTypeMismatch SA01" \
         -i "pandas.infer_freq SA01" \
-        -i "pandas.interval_range RT03" \
         -i "pandas.io.formats.style.Styler.apply RT03" \
         -i "pandas.io.formats.style.Styler.apply_index RT03" \
         -i "pandas.io.formats.style.Styler.background_gradient RT03" \

pandas/core/indexes/interval.py

@@ -1138,6 +1138,7 @@ def interval_range(
     Returns
     -------
     IntervalIndex
+        Object with a fixed frequency.
 
     See Also
     --------