Expose shader validation (#4811)

Co-authored-by: Connor Fitzgerald <[email protected]>

wgpu-core/src/lib.rs

@@ -66,7 +66,11 @@ pub mod registry;
 pub mod resource;
 pub mod storage;
 mod track;
-mod validation;
+// This is public for users who pre-compile shaders while still wanting to
+// preserve all run-time checks that `wgpu-core` does.
+// See <https://github.com/gfx-rs/wgpu/issues/3103>, after which this can be
+// made private again.
+pub mod validation;
 
 pub use hal::{api, MAX_BIND_GROUPS, MAX_COLOR_ATTACHMENTS, MAX_VERTEX_BUFFERS};