add annotation for multiprocessing.{Value,Array} with special c-types (#11833)

test_cases/stdlib/check_multiprocessing.py

@@ -0,0 +1,14 @@
+from __future__ import annotations
+
+from ctypes import c_char, c_float
+from multiprocessing import Array, Value
+from multiprocessing.sharedctypes import Synchronized, SynchronizedString
+from typing_extensions import assert_type
+
+string = Array(c_char, 12)
+assert_type(string, SynchronizedString)
+assert_type(string.value, bytes)
+
+field = Value(c_float, 0.0)
+assert_type(field, Synchronized[float])
+field.value = 1.2