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

src/catch2/catch_capture_matchers.cpp

@@ -5,8 +5,8 @@
  *  Distributed under the Boost Software License, Version 1.0. (See accompanying
  *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  */
-#include "catch_capture_matchers.h"
-#include "catch_interfaces_registry_hub.h"
+#include <catch2/catch_capture_matchers.h>
+#include <catch2/catch_interfaces_registry_hub.h>
 
 namespace Catch {