app,io/pointer: [API] remove CursorNameOp and rename CursorName -> Cursor

It's now possible to directly user pointer.Cursor to add to the ops.

   pointer.CursorText.Add(gtx.Ops)

This is an API change. Use pointer.Cursor directly instead of CursorNameOp.

Signed-off-by: Egon Elbre <egonelbre@gmail.com>

io/system/decoration.go

@@ -49,10 +49,10 @@ const (
 	ActionResizeSouthEast
 )
 
-// CursorName returns the cursor for the action.
+// Cursor returns the cursor for the action.
 // It must be a single action otherwise the default
 // cursor is returned.
-func (a Action) CursorName() pointer.CursorName {
+func (a Action) Cursor() pointer.Cursor {
 	switch a {
 	case ActionResizeNorthWest:
 		return pointer.CursorNorthWestResize