feat(profiles-s-z): vim syntax support

Add vim modeline instructing the editor to use the syntax plugin provided by apparmor.

Continuation of #379, #380, #381, #390 to keep the diff list relatively short.

apparmor.d/profiles-s-z/steam-runtime

@@ -80,4 +80,6 @@ profile steam-runtime @{exec_path} flags=(attach_disconnected) {
   /dev/tty rw,
 
   include if exists <local/steam-runtime>
-}
+}
+
+# vim:syntax=apparmor