1.1.1.1: clarify DoH/DoT on the debug page

A few questions have recently popped up on the forum wondering why “Using DNS over HTTPS” shows as No on 1.1.1.1/help, and the problem was that they weren’t using Cloudflare’s 1.1.1.1 for DoH/DoT. This should be clarified that the debug page will only detect when using 1.1.1.1.