examples/shaders/shared: remove unused feature(lang_items).

Author: eddyb

examples/shaders/shared/src/lib.rs

@@ -1,6 +1,6 @@
 //! Ported to Rust from <https://github.com/Tw1ddle/Sky-Shader/blob/master/src/shaders/glsl/sky.fragment>
 
-#![cfg_attr(target_arch = "spirv", no_std, feature(lang_items))]
+#![cfg_attr(target_arch = "spirv", no_std)]
 
 use core::f32::consts::PI;
 use glam::{vec3, Vec3};