The docs claimed a test would pass that actually wouldn't pass. Repaired

the example so it does pass.

Doc/lib/libdoctest.tex

@@ -501,7 +501,7 @@ Some details you should read once, but won't need to remember:
   case where you need to test a \exception{SyntaxError} that omits the
   traceback header, you will need to manually add the traceback header
   line to your test example.
-  
+
 \item For some \exception{SyntaxError}s, Python displays the character
   position of the syntax error, using a \code{\^} marker:
 
@@ -520,6 +520,7 @@ SyntaxError: invalid syntax
 
 \begin{verbatim}
 >>> 1 1
+Traceback (most recent call last):
   File "<stdin>", line 1
     1 1
     ^