Extract WStrUnits to sys_common::wstr This commit extracts WStrUnits from sys::windows::args to sys_common::wstr. This allows using the same structure for other targets which use wtf8 (example UEFI). This was originally a part of https://github.com/rust-lang/rust/pull/100316 Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>