New keybinding for SplitDown and SplitRight do not work on Windows

[zoof]

I added:

[bindings]
keys =[
	{ key = "d", with = "control | alt", action="SplitDown"},
	{ key = "r", with = "control | alt", action="SplitRight"},
	{ key = "tab", with = "control", action="SelectNextSplitOrTab"}
]

to config.toml file. While the last bind to switch splits or tabs works, the first two do not. I haven't experimented with Linux much yet, but my recollection is that the first two worked on the Flatpak installation of rio on a BlueFin Linux installation.

[olaf-rogalsky]

possibly related to #1275