[clang] [clang] Support DecompositionDecl in -ast-print (PR #221711)

[Ran Regev via cfe-commits]

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@@ -0,0 +1,89 @@
+// RUN: %clang_cc1 -std=c++26 -ast-print %s | FileCheck %s
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regevran wrote:

Yes, [packs](https://github.com/cplusplus/papers/issues/294), a closed issue, with labels C++26 and plenary-approved, needed [here](https://github.com/llvm/llvm-project/pull/221711/changes#diff-96b998278daafafb6d7cc2b4b0c7fe3262baced0e8cc9a92c650d5cb7963f4b1R69-R76).

https://github.com/llvm/llvm-project/pull/221711