Add sdlkeycode.inc

Author: Free-Pascal-meets-SDL-Website

units/sdl2.pas

@@ -180,6 +180,7 @@ interface
 {$I sdlmessagebox.inc}           // 2.0.14
 {$I sdlrenderer.inc}             // 2.0.22
 {$I sdlscancode.inc}             // 2.26.2
+{$I sdlkeycode.inc}
 {$I sdlkeyboard.inc}             // 2.24.1
 {$I sdlmouse.inc}                // 2.0.24
 {$I sdlguid.inc}                 // 2.24.0