bpo-37116: Use PEP 570 syntax for positional-only parameters. (GH-13700)

diff --git a/Lib/random.py b/Lib/random.py
index 53981f3..365a019 100644
--- a/Lib/random.py
+++ b/Lib/random.py
@@ -100,7 +100,7 @@
         self.seed(x)
         self.gauss_next = None
 
-    def __init_subclass__(cls, **kwargs):
+    def __init_subclass__(cls, /, **kwargs):
         """Control how subclasses generate random integers.
 
         The algorithm a subclass can use depends on the random() and/or