Fix: Win32 no longer hides cursor when hovering title bar.

[eigenbom]

• Has this change been discussed on the forum or in an issue before?
• Does the code follow the SFML Code Style Guide?
• Have you provided some example/test code for your changes?

---

Description

This PR is related to issue #1569.

When you hide the mouse cursor in Windows the cursor does not re-appear when hovering the title bar and window frame. It does re-appear on other platforms and also re-appears if you set a blank image cursor - this patch fixes this inconsistency.

Tasks

• Tested on Windows

How to test this PR?

Hover over the title bar or window frame and the cursor should re-appear.

#include <SFML/Window.hpp>
int main()
{
    sf::Window window(sf::VideoMode(400, 300), "Cursor Bug");
    window.setMouseCursorVisible(false);
    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event))
        {
            if (event.type == sf::Event::Closed)
                window.close();
        }
        window.display();
    }
}

[LaurentGomila]

Looks good.