message: doc(interface-types) Update `from_interface_values`'s doc.
  Using `InterfaceValue::Record` explicitely doesn't change anything
  since values are flatten, but it's better for a usual reading to avoid
  confusion.
diff: @@ -36,11 +36,11 @@ use std::{
  /// y: f32,
  /// };
  ///
  -/// let values = vec![
  +/// let values = vec![InterfaceValue::Record(vec![
  /// InterfaceValue::String("abc".to_string()),
  /// InterfaceValue::Record(vec![InterfaceValue::I32(1), InterfaceValue::I64(2)]),
  /// InterfaceValue::F32(3.),
  -/// ];
  +/// ])];
  /// let t = from_interface_values::<T>(&values).unwrap();
  ///
  /// assert_eq!(
  @@ -513,7 +513,7 @@ mod tests {
  #[derive(Deserialize, Debug, PartialEq)]
  struct S(i8);
  - let input = vec![InterfaceValue::S8(42)];
  + let input = vec![InterfaceValue::Record(vec![InterfaceValue::S8(42)])];
  let output = S(42);
  assert_eq!(from_interface_values::<S>(&input).unwrap(), output);
  