[3.12] gh-123789: secrets.randbits returns only non-negative int (GH-123801) (#123831)

gh-123789: `secrets.randbits` returns only non-negative int (GH-123801)
(cherry picked from commit beee91c)

Co-authored-by: Wulian <[email protected]>

Author: miss-islington

Doc/library/secrets.rst

@@ -52,7 +52,7 @@ randomness that your operating system provides.
 
 .. function:: randbits(k)
 
-   Return an int with *k* random bits.
+   Return a non-negative int with *k* random bits.
 
 
 Generating tokens