start in current directory

[mintty]

If wslbridge is run from a non-WSL (cygwin/Windows) working directory and nothing is done to change the directory (like -C~ or WSL startup commands), the WSL shell normally starts in the current working directory (transformed to WSL path).
If wslbridge is run from a directory inside the WSL rootfs path, this does not work and the shell starts in the WSL / directory.