Closes #15213: update comment for _PyOS_URandom
diff --git a/Python/random.c b/Python/random.c
index 73e3cc3..d615923 100644
--- a/Python/random.c
+++ b/Python/random.c
@@ -224,8 +224,9 @@
     }
 }
 
-/* Fill buffer with size pseudo-random bytes, not suitable for cryptographic
-   use, from the operating random number generator (RNG).
+/* Fill buffer with size pseudo-random bytes from the operating system random
+   number generator (RNG). It is suitable for for most cryptographic purposes
+   except long living private keys for asymmetric encryption.
 
    Return 0 on success, raise an exception and return -1 on error. */
 int