doc: Update COPYRIGHT link (#377)

* doc: Update COPYRIGHT link

* doc: Clean up copyright comments

Author: reddevilmidzy

src/dir/mod.rs

@@ -1,6 +1,4 @@
-// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
+// Copyright 2015 The Rust Project Developers.
 //
 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license