Add operation mode in USC Type C interface on `kudu6`

[eevmanu]

I believe there's an opportunity to improve the precision of the documentation regarding the operation mode of the USB-C interface.

https://github.com/system76/tech-docs/blob/master/src/models/kudu6/README.md?plain=1#L55

I think it would be helpful to specify that it's USB 3.2 Gen 2x1, as adding the x1 could help clarify the bandwidth limitations of this interface.

I ran the usb-devices command and was able to observe this information:

...
T: Bus=04 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=10000 MxCh= 2
D: Ver= 3.10 Cls=09(hub ) Sub=00 Prot=03 MxPS= 9 #Cfgs= 1
...
T: Bus=02 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=10000 MxCh= 2
D: Ver= 3.10 Cls=09(hub ) Sub=00 Prot=03 MxPS= 9 #Cfgs= 1
...

This would allow us to manage expectations more accurately (up to 10 Gbit/s) and avoid potential confusion that this interface might be USB 3.2 Gen 2x2 with a capacity of up to 20 Gbit/s.

If I'm mistaken about this, I'd be happy to be corrected and learn from it, as I may have made an incorrect assumption.

Thanks.