[docs] Added a note on how to use pmd to search for unused code in parrot
[docs] Added a note on how to use pmd to search for unused code in parrot


git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@17567 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot