fix up some C signatures (#14624)

a few issues exposed after https://github.com/python/mypy/pull/18259 was merged

stubs/networkx/networkx/utils/misc.pyi

@@ -1,6 +1,7 @@
 import random
+import sys
 from types import ModuleType
-from typing_extensions import TypeAlias
+from typing_extensions import Self, TypeAlias
 
 import numpy
 
@@ -36,6 +37,10 @@ def create_random_state(random_state=None): ...
 
 class PythonRandomViaNumpyBits(random.Random):
     def __init__(self, rng: numpy.random.Generator | None = None) -> None: ...
+    if sys.version_info < (3, 10):
+        # this is a workaround for pyright correctly flagging an inconsistent inherited constructor, see #14624
+        def __new__(cls, rng: numpy.random.Generator | None = None) -> Self: ...
+
     def getrandbits(self, k: int) -> int: ...
 
 class PythonRandomInterface: