[meta] Add cdsl facilities for encodings and recipes;

Co-authored-by: Benjamin Bouvier <public@benj.me>
Co-authored-by: bjorn3 <bjorn3@users.noreply.github.com>

cranelift/codegen/meta/src/cdsl/mod.rs

@@ -6,10 +6,12 @@
 #[macro_use]
 pub mod ast;
 pub mod cpu_modes;
+pub mod encodings;
 pub mod formats;
 pub mod instructions;
 pub mod isa;
 pub mod operands;
+pub mod recipes;
 pub mod regs;
 pub mod settings;
 pub mod type_inference;