Remove roles from WANTED

http://doc.perl6.org/language/objects#Roles covers them.
If anybody wants more materials on roles, please be more specific
in your requests.

Author: moritz

WANTED

@@ -3,7 +3,6 @@ Here is a loose, incomplete collection about what docs need to be written
 Tutorials:
     * general Perl 6 intro
     * multis / multi dispatch, how to use them practically
-    * roles
     * lazy lists and generators
     * concurrency
     * IO