Change return to void in singleton test case

Author: hsutter

regression-tests/pure2-singleton-and-static.cpp2

@@ -1,7 +1,7 @@
 
 test: @singleton type = {
     value: int = 42;
-    print: (this) = std::cout << "(value)$\n";
+    print: (this) = { std::cout << "(value)$\n"; }
 }
 
 main: () = {

regression-tests/test-results/cpp2_post_build.sh

@@ -1,3 +1,3 @@
-Microsoft (R) C/C++ Optimizing Compiler Version 19.50.35721 for x64
+Microsoft (R) C/C++ Optimizing Compiler Version 19.50.35722 for x64
 Copyright (C) Microsoft Corporation.  All rights reserved.
 

regression-tests/test-results/gcc-14-c++2b/pure2-singleton-and-static.cpp.output

@@ -19,7 +19,7 @@ class test;
 #line 2 "pure2-singleton-and-static.cpp2"
 class test {
     private: int value {42}; 
-    public: [[nodiscard]] auto print() const& -> decltype(auto);
+    public: auto print() const& -> void;
     private: explicit test();
 public: [[nodiscard]] static auto instance() -> test&;
 
@@ -36,7 +36,7 @@ auto main() -> int;
 #line 1 "pure2-singleton-and-static.cpp2"
 
 #line 4 "pure2-singleton-and-static.cpp2"
-    [[nodiscard]] auto test::print() const& -> decltype(auto) { return std::cout << "" + cpp2::to_string(value) + "\n";  }
+    auto test::print() const& -> void{std::cout << "" + cpp2::to_string(value) + "\n"; }
 
     test::test(){}
 [[nodiscard]] auto test::instance() -> test&{