Refs #36862 -- Reiterated security note on both variants of RemoteUserMiddleware.

Author: jacobtylerwalls

docs/ref/middleware.txt

@@ -576,7 +576,8 @@ Customize the login URL or field name for authenticated views with the
 .. class:: RemoteUserMiddleware
 
     Middleware for utilizing web server provided authentication. See
-    :doc:`/howto/auth-remote-user` for usage details.
+    :doc:`/howto/auth-remote-user` for usage details, including security
+    considerations.
 
 .. class:: PersistentRemoteUserMiddleware