[3.13] Docs: fix RFC index reference for TLS 1.3 (GH-142262) (#142341)

Docs: fix RFC index reference for TLS 1.3 (GH-142262)
(cherry picked from commit 61823a5)

Co-authored-by: Y. Z. Chen <754097987@qq.com>

Author: miss-islington

Lib/ssl.py

@@ -186,7 +186,7 @@ class _TLSContentType:
 class _TLSAlertType:
     """Alert types for TLSContentType.ALERT messages
 
-    See RFC 8466, section B.2
+    See RFC 8446, section B.2
     """
     CLOSE_NOTIFY = 0
     UNEXPECTED_MESSAGE = 10

Lib/test/test_ssl.py

@@ -5385,7 +5385,7 @@ def test_tlsalerttype(self):
         class Checked_TLSAlertType(enum.IntEnum):
             """Alert types for TLSContentType.ALERT messages
 
-            See RFC 8466, section B.2
+            See RFC 8446, section B.2
             """
             CLOSE_NOTIFY = 0
             UNEXPECTED_MESSAGE = 10