RGFW backend: add missing Right Control key

src/platforms/rcore_desktop_rgfw.c

@@ -175,6 +175,7 @@ static const unsigned short keyMappingRGFW[] = {
     [RGFW_superL] = KEY_LEFT_SUPER,
     #ifndef RGFW_MACOS
     [RGFW_shiftR] = KEY_RIGHT_SHIFT,
+    [RGFW_controlR] = KEY_RIGHT_CONTROL,
     [RGFW_altR] = KEY_RIGHT_ALT,
     #endif
     [RGFW_space] = KEY_SPACE,