Remove Starter tier from Email page

Replace Starter tier badge on Email from GitLab page.

doc/tools/email.md

@@ -5,9 +5,9 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 type: howto, reference
 ---
 
-# Email from GitLab **(STARTER ONLY)**
+# Email from GitLab **(PREMIUM SELF)**
 
-GitLab provides a simple tool to administrators for emailing all users, or users of
+GitLab provides a tool to administrators for emailing all users, or users of
 a chosen group or project, right from the Admin Area. Users receive the email
 at their primary email address.