Function libnotcurses_sys::ncplane_putwegc_stained

pub unsafe extern "C" fn ncplane_putwegc_stained(
    n: *mut ncplane, 
    gclust: *const wchar_t, 
    sbytes: *mut c_int
) -> c_int

Replace the EGC underneath us, but retain the styling. The current styling of the plane will not be changed.