Add comment for `RotationDesignable`
Add comment for `RotationDesignable`

IBAnimatable/IBAnimatable,JakeLin/IBAnimatable,JakeLin/IBAnimatable,IBAnimatable/IBAnimatable,seanwoodward/IBAnimatable,seanwoodward/IBAnimatable,IBAnimatable/IBAnimatable,alexiosdev/IBAnimatable,alexiosdev/IBAnimatable