Theorem: Pos.add_succ (Extra/Pos/Lemmas.lean)

State before:
x y : Pos
⊢ x + (y + 1) = x + y + 1
Tactic:
by_toNat
State after:
x y : Pos
⊢ x.toNat + (y.toNat + 1) = x.toNat + y.toNat + 1

State before:
x y : Pos
⊢ x.toNat + (y.toNat + 1) = x.toNat + y.toNat + 1
Tactic:
exact Nat.add_succ ..
State after:
no goals