Fix minor doc typos

src/libstd/str.rs

@@ -1,4 +1,4 @@
-// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -417,7 +417,7 @@ pub struct CharSplitsN<'a, Sep> {
     priv invert: bool,
 }
 
-/// An iterator over the words of a string, separated by an sequence of whitespace
+/// An iterator over the words of a string, separated by a sequence of whitespace
 pub type Words<'a> =
     Filter<'a, &'a str, CharSplits<'a, extern "Rust" fn(char) -> bool>>;