permitopen= IPv6 format

[Frank Mohr]

Hi

one question about the IPv6 format in permitopen=. 

Is this ":::/port" used anywhere else? 
The only documented format for literal IPv6 addresses I found 
was RFC 2732 as it's used in web-browsers.
They specify the address as "[:::]:port"

In OpenSSH this would be matched by changing 
"%255[^/]/%5[0-9]" to "%*[[]%255[^]]%*[]]:%5[0-9]" in 
the auth-options.c

Frank