[clang] [Clang][diagnostics] Fix structured binding shadows template param loc (PR #129116)

[Erich Keane via cfe-commits]

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@@ -162,3 +162,10 @@ struct A {
 };
 A<0>::B a;
 }
+
+template <typename T> void shadow() {  // expected-note{{template parameter is declared here}}
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erichkeane wrote:

Please instantiate this template as well.

https://github.com/llvm/llvm-project/pull/129116