We had a bunch of `cfg!(windows)` and `cfg!(macos)` which should
have been `cfg!(target_os = "windows")`.
I wonder what the effects of this PR will be fore Windows 😬
* Bug fix: reset repaint countdown when we pass it
* eframe: debug-print what winit event caused a repaint
* egui-winit: don't repaint when only moving window
* fix docstring