message: Fix record Display to support pprint
  Summary:
  This mostly means properly supporting "alternate" display and
  propagating that to contained items (the easier to screw up part). There's
  utilities in starlark-rust to help implement this consistently with other
  starlark types.
diff: @@ -130,15 +130,7 @@ pub struct RecordGen<V> {
  impl<'v, V: ValueLike<'v>> Display for RecordGen<V> {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
  - write!(f, "record(")?;
  - for (i, (name, typ)) in self.iter().enumerate() {
  - if i != 0 {
  - write!(f, ", ")?;
  - }
  - write!(f, "{}=", name)?;
  - Display::fmt(&typ, f)?;
  - }
  - write!(f, ")")
  + display_keyed_container(f, "record(", ")", "=", self.iter())
  }
  }
  