Standardize on `rotation` instead of `angle` for clockwise rotation measured in degrees

[cspotcode]

Enhancement request:

What should be added/changed?

Adopt rotation property name for getting/setting rotation of something in degrees. Deprecate the angle getter/setter.

Rotation describes it better: it is the rotation of the object. The object does not have an "angle", it is rotated.

What would it help with?

Consistency with pyglet. Probably easier for non-native English speakers, too. Comparing the definitions of angle and rotation:

https://www.google.com/search?q=define%3A+angle

angle (n)
the space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.
a particular way of approaching or considering an issue or problem.

https://www.google.com/search?q=define%3Arotation

rotation (n)
the action of rotating around an axis or center.

Tasks

• Add rotation property for everything that has angle today
• Deprecate angle properties, suppress it from appearing in docs via sphinx :private: marker
• Refactor all examples and internal code to use rotation instead of angle

[cspotcode]

We talked a bit on Discord, doesn't sound like there's an appetite for this. https://discord.com/channels/458662222697070613/458662458198982676/1143181877662982164