DOC: Add docstrings to fixtures in /series/methods/test_drop_duplicat…

…es.py (#59265)

* Add docstrings to fixtures in /series/methods/test_drop_duplicates.py

* fixup! Add docstrings to fixtures in /series/methods/test_drop_duplicates.py

pandas/tests/series/methods/test_drop_duplicates.py

@@ -75,10 +75,16 @@ class TestSeriesDropDuplicates:
         params=["int_", "uint", "float64", "str_", "timedelta64[h]", "datetime64[D]"]
     )
     def dtype(self, request):
+        """
+        Fixture that provides different data types for testing.
+        """
         return request.param
 
     @pytest.fixture
     def cat_series_unused_category(self, dtype, ordered):
+        """
+        Fixture that creates a Categorical Series with some unused categories.
+        """
         # Test case 1
         cat_array = np.array([1, 2, 3, 4, 5], dtype=np.dtype(dtype))
 
@@ -141,7 +147,9 @@ def test_drop_duplicates_categorical_non_bool_keepfalse(
 
     @pytest.fixture
     def cat_series(self, dtype, ordered):
-        # no unused categories, unlike cat_series_unused_category
+        """
+        Fixture that creates a Categorical Series with no unused categories.
+        """
         cat_array = np.array([1, 2, 3, 4, 5], dtype=np.dtype(dtype))
 
         input2 = np.array([1, 2, 3, 5, 3, 2, 4], dtype=np.dtype(dtype))