Distinction between MouseMotion and CursorMoved events is unclear in docs

[alice-i-cecile]

What problem does this solve or what need does it fill?

As shown in the mouse_input_events example, Bevy exposes both a MouseMotion and CursorMoved event type.

These are poorly documented, but it appears that MouseMotion is relative, while CursorPosition is absolute (and tied to a specific window).

What solution would you like?

Clearly differentiate these types in the docs and explain why they both exist (and when you should use one vs the other).

What alternative(s) have you considered?

Remove MouseMotion, and only expose CursorMoved. However, it's not clear if MouseMotion can always be reconstructed; I'm particularly nervous about what happens when the cursor is locked to the screen.

Additional context

Related to #5034, which also tries to simplify the UX here.

[alice-i-cecile]

It's also not clear why one refers to "mouse" and the other refers to "cursor". Perhaps there's a significance to this upstream in winit?

[alice-i-cecile]

And of course, MouseMotion is stored in bevy_input, while CursorMoved comes from bevy_window.

[DJMcNab]

My understanding is that mouse motion is about the physical motion of the actual mouse - this ignores pointer acceleration for example.

Cursor movement is about the movement of the cursor, i.e. the thing that you use to click with.