regReplacePath function
Replaced the existing Windows PATH with newPaths.
WARNING: becareful using this method. If you get it wrong
you can destroy your Windows PATH which will stop lots
of things (everything?) from working.
A WindowsException is thrown the call falls.
@Throwing(WindowsException)
Implementation
void regReplacePath(List<String> newPaths) => _userPath.replace(newPaths);