Rewrite includes inside the library to use <catch2/> form

src/catch2/catch_assertionresult.h

@@ -9,11 +9,11 @@
 #define TWOBLUECUBES_CATCH_ASSERTIONRESULT_H_INCLUDED
 
 #include <string>
-#include "catch_assertioninfo.h"
-#include "catch_result_type.h"
-#include "catch_common.h"
-#include "catch_stringref.h"
-#include "catch_assertionhandler.h"
+#include <catch2/catch_assertioninfo.h>
+#include <catch2/catch_result_type.h>
+#include <catch2/catch_common.h>
+#include <catch2/catch_stringref.h>
+#include <catch2/catch_assertionhandler.h>
 
 namespace Catch {