Move macro to the correct Erlang app

The Web MQTT link is not used in the rabbitmq_mqtt Erlang app.
This link is only used in the rabbitmq_web_mqtt Erlang app.
Hence, move the link to the correct Erlang app.

(cherry picked from commit 4b95745)

deps/rabbitmq_mqtt/include/rabbit_mqtt.hrl

@@ -12,7 +12,6 @@
 -define(PERSISTENT_TERM_EXCHANGE, mqtt_exchange).
 -define(DEFAULT_MQTT_EXCHANGE, <<"amq.topic">>).
 -define(MQTT_GUIDE_URL, <<"https://rabbitmq.com/docs/mqtt/">>).
--define(WEB_MQTT_GUIDE_URL, <<"https://rabbitmq.com/docs/web-mqtt/">>).
 
 -define(MQTT_TCP_PROTOCOL, 'mqtt').
 -define(MQTT_TLS_PROTOCOL, 'mqtt/ssl').

deps/rabbitmq_web_mqtt/src/Elixir.RabbitMQ.CLI.Ctl.Commands.ListWebMqttConnectionsCommand.erl

@@ -59,7 +59,7 @@ usage_additional() ->
     ].
 
 usage_doc_guides() ->
-    [?WEB_MQTT_GUIDE_URL].
+    [<<"https://rabbitmq.com/docs/web-mqtt">>].
 
 run(Args, #{node := NodeName,
             timeout := Timeout,