Rename 'plaintextproxy' to 'homeserver-url'

Pantalaimon/proxies are not the only use-case for not using automatic discovery.

Author: progval

README.md

@@ -78,6 +78,7 @@ Two notes on this screenshot:
   * no SSL/TLS
   * SASL username: your full matrix ID (`user:homeserver.example.org`)
   * SASL password: your matrix password
+  * (Optional / advanced configuration) If you cannot use homeserver URL discovery, configure `homeserver-url=https://homeserver.example.org` as your IRC client's GECOS/"real name"
 
 See below for extra instructions to work with web clients.
 
@@ -87,7 +88,7 @@ See `INSTALL.md` for a more production-oriented guide.
 
 Matrix2051 does not support Matrix's end-to-end encryption (E2EE), but can optionally be used with [Pantalaimon](https://github.com/matrix-org/pantalaimon).
 
-To do so, setup Pantalaimon locally, and configure `plaintextproxy=http://localhost:8009` as your IRC client's GECOS/"real name".
+To do so, setup Pantalaimon locally, and configure `homeserverurl=http://localhost:8009` as your IRC client's GECOS/"real name".
 
 ## Architecture
 

lib/irc/handler.ex

@@ -441,9 +441,11 @@ defmodule M51.IrcConn.Handler do
                       {:ok, {local_name, hostname}} ->
                         user_id = authcid
 
+                        # Keep deprecated alias "plaintextproxy" that was used back when
+                        # this was only meant to be used with Pantalaimon
                         proxy =
                           case Regex.named_captures(
-                                 ~R(plaintextproxy=(?<url>https?://\S*\)),
+                                 ~R((plaintextproxy|homeserver-url)=(?<url>https?://\S*\)),
                                  M51.IrcConn.State.gecos(state)  || ""
                                ) do
                             nil -> nil