Copter: Auto mode CONDITION_YAW treats neg relative angle with CCW direction as CCW

[rmackay9]

This makes Auto mode's handling of the CONDITION_YAW command slightly more intuitive in the case where the user has specified both a negative relative angle and a CCW direction (e.g. Deg = -90, Dir = -1, Relative=1).

Currently master interprets this double negative as a positive and will rotate the vehicle in the clockwise direction. With this change the double negative is interpreted as a negative and so the vehicle rotates in the CCW direction.

This PR also includes some drive-by formatting fixes.

This has been lightly tested in SITL and works as expected.

Note that CONDITION_YAW can also be sent as an immediate command (e.g. while the vehicle is GUIDED mode) but that handler rejects negative angles so the double-negative case is never met. We could them consistent by removing these few lines and the modify the MAVLink spec (see related PR)

There is a related MAVLink PR here ArduPilot/mavlink#341 (related but no dependency)

This resolves issue #23874

[lthall]

I don't think this is correct. The CW/CCW define the positive direction and the angle is unambiguous.

This approach means we are changing the definition of angle based on the direction of "positive turn".

I think the current approach both makes sense and is "correct" from a mathematical/engineering perspective. Further the cost of making this mistake is low.

[IamPete1]

We could add a pre-arm mission check for the double negative.

[lthall]

We could add a pre-arm mission check for the double negative.

Yes, This option would still be "correct". This would make it consistent with the mavlink yaw message I believe.

[rmackay9]

OK, I'll go ahead and close this despite all the work I put into making the pretty PR description..

I've been slightly naughty and directly cherry-picked the formatting fix into master.