Issue 6180 - use ABP_TEXT everywhere in order to let String be a UTF-8 string

test/compiled/user-config-test-abp-utf8-string.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus. If not, see <http://www.gnu.org/licenses/>.
  */
 
 #pragma once
 
-#define ABP_NS test_abp_core
+#define ABP_UTF8_STRING
+
+#define ABP_NS abp_core
 #define ABP_NS_BEGIN namespace ABP_NS {
 #define ABP_NS_END }
 #define ABP_NS_USING using namespace ABP_NS;