The light.mqtt component supports the 'retain' config parameter, which is important for many MQTT based lights. It is referenced in the explanation paragraph, but was not in the config parameter listing.
For the second example, the brightness functionality was mentioned, but it doesn't include the "brightness_state_topic" and the "brightness_command_topic" instructions.
* Basic MQTT light example (ESP8266)
Add a basic example to control a led with MQTT and the light component (ESP8266)
* Corrections + new example
The example is moved from the warnings' section. Add another example for a RGB led.
