Yay, CookieRevised is indeed correct.
Semicolins are generally for new
sentences. "modify messages you send and modify messages you receive" is not a complete sentence. This could be rewritten as "modify messages you send and receive" though
However, I found another small mistake. In the Contact List Cleanup, the wording at the top should be "... Use it to find contacts you do not chat with..." (no "out").