Fix `#include` directive for catch-main cpp file

src/dds/build.cpp

 
     auto catch_cpp = test_include_root / "catch2" / fname;
     auto cpp_strm  = open(catch_cpp, std::ios::out | std::ios::binary);
-    cpp_strm << R"(#include "./catch.hpp"\n)";
+    cpp_strm << "#include \"./catch.hpp\"\n";
     cpp_strm.close();
 
     auto sf = source_file::from_path(catch_cpp, test_include_root);