Add docs for 0x57

[thparamboll]

Hi,

In this pull request for libratbag I add support for setting LED color on the G9. It uses the 0x57 that you have marked as ? in the docs.

If you want a column for the G9 in your table as well, then I can add what I find for that mouse.

[cvuchener]

Thanks.

Any addition to the documentation is welcome : supported reports, difference in parameters, .... I don't think I will right code for other mice in this repo but I would like the documentation to be as general as possible. Or you can fork it/rewrite it if you want to maintain/collect all this data yourself. It would be nice to have all the documentation about Logitech devices in one place.

[hanetzer]

@cvuchener Just ran into your repo here, and I have much the same idea with GSeriesDev/gseries-tools; on that note, would you like to pool our efforts on documenting and supporting these devices? I currently own a G105 keyboard and G602 mouse and have ssh access to a machine with a G19 and G930, plus a few odd friends on freenode with a few other devices willing to help with documenting and testing

[cvuchener]

Are they HID++ devices? Although I don't know much about it, I can add some HID++ 2.0 documentation as it has a lot in common with HID++ 1.0. But there are other devices with completely different protocols (G300 and G600 according to Thomas Andersen and Benjamin Tissoires).

PS: Please create your own issue for discussion. This one is about register 0x57 for HID++ 1.0.
PS2: I have seen your report descriptors for the G105, it is not a HID++ device.