Add events for the scroll wheel in Linux.

[SaVe-27]

My project uses several widgets, however I notice that the scroll wheel does not work on Linux.

In these two files, I add the events to buttons 4 and 5 (along with MouseWheel for Windows and MacOS) and assign a value for each interaction with button 4 (or 5).

Warning

I warn everyone about adding more events with other buttons (1, 2 and 3): in this case, these events maybe affect the user experience with the scroll wheel on Linux, because they interact with the conditional in self._parent_canvas.(x|y )view.

Thank you.

[FedericoSpada]

Hi,
can you make your changes more similar to the ones made here? #2515
In particular:

• Button-4 and Button-5 bindings are done only for Linux system;
• xview_scroll() is called with -1/1 values instead of -10/10 (or maybe, can you justify why you used 10? Since I don't have Linux, I can't try for myself).

Finally, for CTkScrollbar, can you separate Button-4 and Button-5 bindings into 2 separate if-statements:

if sequence is None or sequence == "<Button-4>":
    self._canvas.bind("<Button-4>", self._mouse_scroll_event)
if sequence is None or sequence == "<Button-5>":
    self._canvas.bind("<Button-5>", self._mouse_scroll_event)

Thanks

[FedericoSpada]

I've replicated the changes in another commit.