Issue 18724: Fix typo noticed by Susan Tan.

diff --cc Doc/library/smtplib.rst
index d5bd906ba46f72701f4c0cafff1ed055980df737,addc6be923b9395560a9170e9708c63e402444bf..a7d15384d09c33a5550e22ca8ad7a58124553205
--- 1/Doc/library/smtplib.rst
--- 2/Doc/library/smtplib.rst
+++ b/Doc/library/smtplib.rst
@@@ -110,8 -110,8 +110,8 @@@ A nice selection of exceptions is defin
  
  .. exception:: SMTPException
  
 -   The base exception class for all the other exceptions provided by this
 -   module.
 +   Subclass of :exc:`OSError` that is the base exception class for all
-    the other excpetions provided by this module.
++   the other exceptions provided by this module.
  
  
  .. exception:: SMTPServerDisconnected