doc: Minor example formatting in 11 References

Author: iliekturtles

src/doc/tutorial.md

@@ -1413,7 +1413,7 @@ contains a point, but allocated in a different location:
 
 ~~~
 # struct Point { x: f64, y: f64 }
-let on_the_stack : Point  =  Point { x: 3.0, y: 4.0 };
+let on_the_stack :  Point =  Point { x: 3.0, y: 4.0 };
 let owned_box    : ~Point = ~Point { x: 7.0, y: 9.0 };
 ~~~