Fixes #551: Update username change instructions

src/backend/templates/views/account/changeUsername.pug

@@ -5,7 +5,12 @@ block bannerMixin
 block content
     .containerCenter
         h2.account-title Change Username
-        h4 Change your username by using the form below. Once it is changed, you can log in to your account with the new username. <br> You can only change the name every 30 days and your old username will be reserved for 6 months. <br> In case you choose an offending username you might get banned.
+        h4 Change your username by using the form below. After renaming, you must log out and log back in with the changed username in the FAF Client to access chat.
+        br
+        p You can change your name every 3 months, and your previous username will be reserved for 6 months.
+        br
+        p FAF Rules apply to usernames as well; violations may result in a ban. For more details, please visit
+        a(href='https://faforever.com/rules') the rules.
         br
         .row
             .col-md-offset-3.col-md-6