message: rust: add rustdoc descriptions to the public API
diff: // Copyright 2019-2020 The Fizzy Authors.
  // SPDX-License-Identifier: Apache-2.0
  +//! This is a Rust interface to [Fizzy](https://github.com/wasmx/fizzy), a WebAssembly virtual machine.
  +//!
  +//! Currently it is only possible to validate inputs, but soon execution will be supported too.
  +
  mod sys;
  +/// Parse and validate the input according to WebAssembly 1.0 rules. Returns true if the supplied input is valid.
  pub fn validate<T: AsRef<[u8]>>(input: T) -> bool {
  unsafe { sys::fizzy_validate(input.as_ref().as_ptr(), input.as_ref().len()) }
  }
  