Issue/template verbage

When a new user begins using osTicket and decides to create/modify their email templates for the first time, it is possible for them to be confused when they arrive at templates.php. This is because the page's table header reads "Email Templates", when in fact, the table is actually a list of "Email Template Sets." Wherein each set they are going to find what they are actually more likely interested in editing. By changing the verbiage on this page, prospective confusion is removed.