Add MovementX and MovementY to relevant MouseEventArgs

[linkdotnet]

.net7.0-preview7 introduced two new properties on the MouseEventArgs: MovementX and MovementY (API diff, current main).

I tried to find in which places the property gets set, but found only a view occurrences (and not even the obvious MouseMoveEvent):

The most obvious case would be to add it to mousemove. Not sure where you need it on onclick.
For starters we could go with that and see if folks need it somewhere else.

[egil]

If we add it to one of the handler trigger methods with all the default arguments, then we should for consistency sake add it to all.

For now, it's a nice to have. Users that want to set these can use the handler trigger method that takes an MouseEventArg as input.

[linkdotnet]

Labelled it as „good first issue“.