Collets level params in more cases

[josojo]

Small modification to collect the level params in more cases.

This eliminates some errors in simulations via the Repl. E.g. the simulation of the following theorem:

theorem exists_not_acc_lt_of_not_acc {a : α} {r} (h : ¬Acc r a) : ∃ b, ¬Acc r b ∧ r b a := by
  contrapose! h
  refine' ⟨_, fun b hr => _⟩
  by_contra hb
  exact h b hb hr
#align rel_embedding.exists_not_acc_lt_of_not_acc RelEmbedding.exists_not_acc_lt_of_not_acc

would throw an error that a level param does not exist.

[yangky11]

Thanks!