Can not scroll buffer when using windows builtin telnet client in cygwin/msys2/vscode terminal etc

[kenifanying]

Hi

I find I can't scroll buffer when using winpty telnet [host] in mintty or telnet [host] in vscode terminal, gvim terminal etc. It's normal using the telnet client in cmd or powershell.

It seems that microsoft's windows terminal has the same problem.

microsoft/terminal#6056