Add copy.replace for 3.13 (#12262)

stdlib/@tests/test_cases/check_copy.py

@@ -0,0 +1,21 @@
+from __future__ import annotations
+
+import copy
+import sys
+from typing_extensions import Self, assert_type
+
+
+class ReplaceableClass:
+    def __init__(self, val: int) -> None:
+        self.val = val
+
+    def __replace__(self, val: int) -> Self:
+        cpy = copy.copy(self)
+        cpy.val = val
+        return cpy
+
+
+if sys.version_info >= (3, 13):
+    obj = ReplaceableClass(42)
+    cpy = copy.replace(obj, val=23)
+    assert_type(cpy, ReplaceableClass)