Documentation of variables should contain information about late expansion using windows

Documentation of variables should contain information about late expansion using windows.

The documentation about using environment variable in windows explains the these can be used using %. However when ever using variables with white spaces (ssh-key, etc) and newlines late expansion ! is needed.

Example:

echo %SSHKEY% > mykey

will fail. One needs to run

echo !SSHKEY! > mykey