Define wasm import module name in Rust

wasm_module.rs

#[link(wasm_import_module = "lunar")]
unsafe extern "C" {
    pub fn get_renderer(input_length: usize) -> i64;
}

#[unsafe(no_mangle)]
pub extern "C" fn add_u32(a: u32, b: u32) -> u32 {
    unsafe {
        let _ = get_renderer(33usize);
    }
    a + b
}