Merge pull request #5 from TonyMistark/master

trait bounds: draw parameter declaration error

Author: aaranxu

src/trait-bounds.md

@@ -40,7 +40,7 @@
 ```rust
 # type Surface = i32;
 trait Shape {
-    fn draw(&self, Surface);
+    fn draw(&self, surface: Surface);
     fn name() -> &'static str;
 }