DEPR: use DeprecationWarning for Categorical fastpath deprecation (#52589)

Author: jorisvandenbossche

pandas/core/arrays/categorical.py

@@ -381,7 +381,7 @@ def __init__(
             warnings.warn(
                 "The 'fastpath' keyword in Categorical is deprecated and will "
                 "be removed in a future version. Use Categorical.from_codes instead",
-                FutureWarning,
+                DeprecationWarning,
                 stacklevel=find_stack_level(),
             )
         else:

pandas/tests/arrays/categorical/test_constructors.py

@@ -36,7 +36,7 @@ def test_fastpath_deprecated(self):
         codes = np.array([1, 2, 3])
         dtype = CategoricalDtype(categories=["a", "b", "c", "d"], ordered=False)
         msg = "The 'fastpath' keyword in Categorical is deprecated"
-        with tm.assert_produces_warning(FutureWarning, match=msg):
+        with tm.assert_produces_warning(DeprecationWarning, match=msg):
             Categorical(codes, dtype=dtype, fastpath=True)
 
     def test_categorical_from_cat_and_dtype_str_preserve_ordered(self):