Inaccurate `intent_file_handler` docs

[ndarilek]

From https://mycroft.ai/documentation/padatious/:

The register_intent_file(intent_file, handler) methods arguments are:

intent_file: the filename of above mentioned intent files without the .intent as argument.

Yet, in my skills:

@intent_file_handler("stop.info")

doesn't work, I have to add the .intent extension.

[MatthewScholefield]

Thanks for finding this issue with the documentation. I've just update that line so that it now says "with the .intent".