Fix enumerate code snippet to run without error message

Code previously added numbers to strings, which results in a TypeError

docs/writing/style.rst

@@ -548,11 +548,11 @@ keep a count of your place in the list.
 .. code-block:: python
 
     for i, item in enumerate(a):
-        print i + ", " + item
+        print i, item
     # prints
-    # 0, 3
-    # 1, 4
-    # 2, 5
+    # 0 3
+    # 1 4
+    # 2 5
 
 The ``enumerate`` function has better readability than handling a counter
 manually. Moreover,