Translate environment variables from Strings to Values. Requires config to be already set up in
case the user defined custom env conversions in config.nu.
Returns the current working directory, which is guaranteed to be canonicalized.
Unlike current_dir_const(), this also considers modifications to the current working directory made on the stack.
Returns the current working directory as a String, which is guaranteed to be canonicalized.
Unlike current_dir_str_const(), this also considers modifications to the current working directory made on the stack.