feat(groups/{u,v,w,x}*): vim syntax support

Add vim modeline instructing the editor to use syntax plugin provided by apparmor.
Continuation of #395 to keep the diff list relatively short.

apparmor.d/groups/whonix/msgcollector-striphtml

@@ -16,4 +16,6 @@ profile msgcollector-striphtml @{exec_path} {
   @{lib}/msgcollector/ r,
 
   include if exists <local/msgcollector-striphtml>
-}
+}
+
+# vim:syntax=apparmor