Made output example in doc of verbosity_exception use a code-like formatting

doc/library/config.txt

@@ -486,6 +486,8 @@ import theano and print the config variable, as in:
     with short names such as ``'Elemwise{add_no_inplace}'``. If ``'high'``,
     some exceptions will also refer to apply nodes with long descriptions like:
 
-	A. Elemwise{add_no_inplace}
-	      B. log_likelihood_v_given_h
-	      C. log_likelihood_h
+    ::
+
+        A. Elemwise{add_no_inplace}
+              B. log_likelihood_v_given_h
+              C. log_likelihood_h