Generic 6DOF Joint - angular limit - values in Inspector are misleading

When editing any [angular limit for a Generic 6DOF joint](https://docs.godotengine.org/en/3.2/classes/class_generic6dofjoint.html#class-generic6dofjoint-property-angular-limit-x-lower-angle) in the inspector, one can enter the values in angles.

However, if one tries to edit the same property in code, the value must be given in radians. And since the Inspector accept angles, it can take a while to figure out the problem.

A single line in the docs, and a hint in the Inspector warning about this is enough in my opinion.