tweak: proxy setup guide URL resolution clarification (#403)

This came up in https://forum.cfx.re/t/5185471.

content/docs/server-manual/proxy-setup.md

@@ -11,9 +11,12 @@ At times, it may be desirable to have a reverse proxy in front of your Cfx.re se
 The client->server connection process is as follows:
 
 1. Client resolves the _connect endpoint_ from the join interaction. This can be any of the following:
-   * The `connectEndPoints` field in the server listing output.
-   * The server address cached by the join URL subsystem.
-   * The raw IP, host or URL entered in a `connect` command.
+   * The `connectEndPoints` field in the server listing output, which can be configured using `sv_listingHostOverride`.
+   * The server address cached by the join URL subsystem, such as from history.
+   * An IP, host or URL entered in a `connect` command. These get processed as follows:
+     * Bare hosts/IPs: `host.example` will resolve to `http://host.example:30120/`.
+     * Hosts with port: `host.example:30121` resolve to `http://host.example:30121/`.
+     * URLs with scheme: `http://host.example/` and `https://host.example/` will be resolved as-is, using the default ports for HTTP and HTTPS (80/443).
 2. Client retrieves general server metadata via a `GET /info.json` on the connect endpoint.
 3. Client attempts an `initConnect` request to the connect endpoint's `POST /client`.
 4. If server accepts client, it'll send a connection token to client.
@@ -144,4 +147,4 @@ This setup can have a few variations as well:
 
 * One could add the load balancer to a Kubernetes cluster as a proper ingress.
 * If specifying a proper `location` block (e.g. a regular expression), the domain could be shared with, say, a web site.
-* Implementing a custom handler for `/client` initConnect requests and delegating a successful connection to the actual backend server's `initConnect` sequence. This could be used for a server picker or some other creative things.
+* Implementing a custom handler for `/client` initConnect requests and delegating a successful connection to the actual backend server's `initConnect` sequence. This could be used for a server picker or some other creative things.