Add description to witx-bindgen

Author: alexcrichton

crates/witx-bindgen/Cargo.toml

@@ -4,6 +4,7 @@ version = "0.1.0"
 authors = ["The Cranelift Project Developers"]
 license = "Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT"
 edition = "2018"
+description = "Utility to turn witx files into Rust source code bindings"
 
 [dependencies]
 heck = "0.3"