Roll sensitivity recommendation

[donstim]

In "Recommended Settings," the documentation currently states, " For roll (left or right) use what you think is best for you. The above-mentioned - 30 % is a good starting point."

I did not realize this was in there and therefore neglected to ask it be changed after incorporating the flight model update of flybywiresim/aircraft#7556. This update was based on using a linear roll sensitivity. The document should be updated to be consistent. (It may be prudent to state that both the recommended pitch and roll sensitivity recommendations are starting points and may need to be adjusted for the specific user's controller(s).)