C++ modernize: Pragma once (#6264)

* Migrate cpp headers to pragma once

src/guiChatConsole.h

@@ -17,8 +17,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
-#ifndef GUICHATCONSOLE_HEADER
-#define GUICHATCONSOLE_HEADER
+#pragma once
 
 #include "irrlichttypes_extrabloated.h"
 #include "modalMenu.h"
@@ -132,7 +131,3 @@ private:
 	gui::IGUIFont *m_font = nullptr;
 	v2u32 m_fontsize;
 };
-
-
-#endif
-