Update Windows instructions

[eminence]

For years, the mosh chrome app was the recommended way to use mosh on Windows. But it seems like this app won't work in the future, see: rpwoodbu/mosh-chrome#223

These days, my personal recommendation to everyone who asks is that they should use WSL with Windows Terminal.

[beedell-roke]

Alternatively, Termius operates well.
Does a PR exist to modify the instructions?

[keithw]

Termius isn't Mosh; it's (said to contain) a dirty-room reimplementation of mosh-client, but we don't really know what's in it.

[beedell-roke]

@keithw, I can't vouch for Termius's mosh compatibility in any meaningful manner, but its mosh support worked when I tested it, although I've since abandoned Termius.