[clang] [Clang][NFC] Mark 3106 as implemented. (PR #192256)

[Vlad Serebrennikov via cfe-commits]

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@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -std=c++98 -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected %s
+// RUN: %clang_cc1 -std=c++11 -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected %s
+// RUN: %clang_cc1 -std=c++14 -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected %s
+// RUN: %clang_cc1 -std=c++17 -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected %s
+// RUN: %clang_cc1 -std=c++20 -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected %s
+// RUN: %clang_cc1 -std=c++23 -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected %s
+// RUN: %clang_cc1 -std=c++2c -fexceptions -fcxx-exceptions -pedantic-errors -verify-directives -verify=expected %s
+
+
+namespace cwg3106 { // cwg3106: yes
+
+constexpr const char*  str = R"(\u{1234})";
----------------
Endilll wrote:

```suggestion
constexpr const char* str = R"(\u{1234})";
```

https://github.com/llvm/llvm-project/pull/192256