message: Fix JS sample code by adding "&mut store"
  `Instance::new` and `.call` need `&mut store` as first argument in order to compile.
diff: //! to compile it with [`wasm-pack`] and [`wasm-bindgen`]:
  //!
  //! ```ignore
  +//! use wasm_bindgen::prelude::*;
  +//! use wasmer::{imports, Instance, Module, Store, Value};
  +//!
  //! #[wasm_bindgen]
  //! pub extern fn do_add_one_in_wasmer() -> i32 {
  //! let module_wat = r#"
  //! let module = Module::new(&store, &module_wat).unwrap();
  //! // The module doesn't import anything, so we create an empty import object.
  //! let import_object = imports! {};
  -//! let instance = Instance::new(&module, &import_object).unwrap();
  +//! let instance = Instance::new(&mut store, &module, &import_object).unwrap();
  //!
  //! let add_one = instance.exports.get_function("add_one").unwrap();
  -//! let result = add_one.call(&[Value::I32(42)]).unwrap();
  +//! let result = add_one.call(&mut store, &[Value::I32(42)]).unwrap();
  //! assert_eq!(result[0], Value::I32(43));
  //!
  //! result[0].unwrap_i32()
  