Fix a typo about a comma. (GH-10306)

(cherry picked from commit fe62d877)
Co-authored-by: İsmail Arılık <arilik.ismail@gmail.com>

Doc/tutorial/errors.rst

@@ -315,7 +315,7 @@ to create specific exception classes for different error conditions::
            self.next = next
            self.msg = msg
 
-Most exceptions are defined with names that end in "Error," similar to the
+Most exceptions are defined with names that end in "Error", similar to the
 naming of the standard exceptions.
 
 Many standard modules define their own exceptions to report errors that may