Add caddy reverse proxy websocket example (#2119)

* Add caddy reverse proxy websocket example

* Use consistent hostname for caddy reverse proxy

docs/MANUAL.md

 ProxyPassReverse /webirc http://127.0.0.1:8067
 ```
 
+On Caddy, websocket proxying can be configured with:
+
+```
+handle_path /webirc {
+  reverse_proxy 127.0.0.1:8067
+}
+```
+
 ## Migrating from Anope or Atheme
 
 You can import user and channel registrations from an Anope or Atheme database into a new Ergo database (not all features are supported). Use the following steps: