Apply suggestions from code review

Co-authored-by: Joe Zemmels (he/him) <jzemmels@gmail.com>

Author: ehinman

dataretrieval/waterdata/api.py

@@ -1655,7 +1655,7 @@ def get_por_stats(
         end_date: Optional[str] = None,
         monitoring_location_id: Optional[Union[str, list[str]]] = None,
         page_size: int = 1000,
-        parent_timeseries_id: Optional[Union[str, list[str]]] = None,
+        parent_time_series_id: Optional[Union[str, list[str]]] = None,
         site_type_code: Optional[Union[str, list[str]]] = None,
         site_type_name: Optional[Union[str, list[str]]] = None,
         parameter_code: Optional[Union[str, list[str]]] = None,
@@ -1756,7 +1756,7 @@ def get_date_range_stats(
         end_date: Optional[str] = None,
         monitoring_location_id: Optional[Union[str, list[str]]] = None,
         page_size: int = 1000,
-        parent_timeseries_id: Optional[Union[str, list[str]]] = None,
+        parent_time_series_id: Optional[Union[str, list[str]]] = None,
         site_type_code: Optional[Union[str, list[str]]] = None,
         site_type_name: Optional[Union[str, list[str]]] = None,
         parameter_code: Optional[Union[str, list[str]]] = None,