Fix whitespace in example

Doc/tut/tut.tex

@@ -4315,11 +4315,11 @@ be trivially easy to create:
 
 \begin{verbatim}
 >>> def reverse(data):
-	for index in range(len(data)-1, -1, -1):
-		yield data[index]
+        for index in range(len(data)-1, -1, -1):
+            yield data[index]
 		
 >>> for char in reverse('golf'):
-	print char
+        print char
 
 f
 l