chore(Combinatorics): restore deprecated pentagonal.lean module (leanprover-community#41397)

Author: wwylele

Mathlib.lean

@@ -3561,6 +3561,7 @@ public import Mathlib.Combinatorics.Enumerative.InclusionExclusion
 public import Mathlib.Combinatorics.Enumerative.Partition.Basic
 public import Mathlib.Combinatorics.Enumerative.Partition.GenFun
 public import Mathlib.Combinatorics.Enumerative.Partition.Glaisher
+public import Mathlib.Combinatorics.Enumerative.Pentagonal
 public import Mathlib.Combinatorics.Enumerative.Pentagonal.Basic
 public import Mathlib.Combinatorics.Enumerative.Pentagonal.PowerSeries
 public import Mathlib.Combinatorics.Enumerative.Pentagonal.Ring

Mathlib/Combinatorics/Enumerative/Pentagonal.lean

@@ -0,0 +1,10 @@
+/-
+Copyright (c) 2026 Weiyi Wang. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+Authors: Weiyi Wang
+-/
+module
+
+public import Mathlib.Combinatorics.Enumerative.Pentagonal.Basic
+
+deprecated_module (since := "2026-07-15")