Explain "failed to set hostkey preference" error somewhere

[msifd]

Hello! Please add somewhere in docs explanation that errors like

$ jj git clone git@github.com:martinvonz/jj.git
Fetching into new repo in "\\?\D:\Dev\jujutsu\jj"
Error: failed to set hostkey preference: The requested method(s) are not currently supported; class=Ssh (23)
Hint: Jujutsu uses libssh2, which doesn't respect ~/.ssh/config. Does `ssh -F /dev/null` to the host work?

(at least on Windows) means you need to fix your .ssh/known_hosts. It took me three days and two computers to figure it out.

So the easy way to fix it is to delete/rename current known_hosts, clone repo using git and agree to create new known_hosts (this time with githubs ssh-ed25519 key).

The root cause was that libssh2 doesn't support ecdsa-sha2-nistp256 keys while git works fine.