replace \033[K with \r in clear

[AskAlice]

seems that in WSL it doesn't actually clear the line when just using \033[K, but it does with \r. In Powershell, however it does clear the line.

this fixes that

[briandowns]

LGTM

[fatih]

This change broke the clearing the lines for our CLI https://github.com/planetscale/cli.

I'm not sure what's going on with WSL, but to fix it, I had to print a new escape sequence:

fmt.Fprint(p.out(), "\033[2K")

The 2K, means to remove the entire line:

Erases part of the line. If n is 0 (or missing), clear from cursor to the end of the line. 
If n is 1, clear from cursor to beginning of the line. If n is 2, clear entire line. 
Cursor position does not change.

Esc[K   Clear line from cursor right   EL0
Esc[0K  Clear line from cursor right   EL0
Esc[1K  Clear line from cursor left    EL1
Esc[2K  Clear entire line              EL2 

https://en.wikipedia.org/wiki/ANSI_escape_code#CSI_(Control_Sequence_Introducer)_sequences

I suggest to revert this change or guard it and only call \r if it detects WSL.

[briandowns]

Change reverted and cutting new release. We will need to address this fix again.

[AskAlice]

detecting the presence of /etc/wsl.conf is the most consistent way, but you can also grep Microsoft /proc/version

[HarryMichal]

Why is \r causing a line to be deleted? I only know it as Carriage Return and I wouldn't expect it to delete lines.