message: feat(fmt_index): impl for DependencyIndex
diff: @@ -38,8 +38,8 @@ impl<Db> crate::debug::DebugWithDb<Db> for DependencyIndex
  where
  Db: ?Sized + Database,
  {
  - fn fmt(&self, f: &mut std::fmt::Formatter<'_>, _db: &Db) -> std::fmt::Result {
  - write!(f, "{:?}", *self) // FIXME
  + fn fmt(&self, f: &mut std::fmt::Formatter<'_>, db: &Db) -> std::fmt::Result {
  + db.fmt_index(*self, f)
  }
  }
  