Move DisplayServer enums and typedefs to DisplayServerEnums

This will allow decoupling `display_server.h` from a number of headers in the
codebase which only require those enums and not all the DisplayServer API.

platform/android/java/lib/src/main/java/org/godotengine/godot/input/GodotEditText.java

@@ -57,7 +57,7 @@ public class GodotEditText extends EditText {
 	private final static int HANDLER_OPEN_IME_KEYBOARD = 2;
 	private final static int HANDLER_CLOSE_IME_KEYBOARD = 3;
 
-	// Enum must be kept up-to-date with DisplayServer::VirtualKeyboardType
+	// Enum must be kept up-to-date with DisplayServerEnums::VirtualKeyboardType
 	public enum VirtualKeyboardType {
 		KEYBOARD_TYPE_DEFAULT,
 		KEYBOARD_TYPE_MULTILINE,

platform/android/java/lib/src/main/java/org/godotengine/godot/tts/GodotTTS.java

@@ -57,7 +57,7 @@ import java.util.Set;
  */
 @Keep
 public class GodotTTS extends UtteranceProgressListener implements TextToSpeech.OnInitListener {
-	// Note: These constants must be in sync with DisplayServer::TTSUtteranceEvent enum from "servers/display/display_server.h".
+	// Note: These constants must be in sync with DisplayServerEnums::TTSUtteranceEvent enum from "servers/display/display_server.h".
 	final private static int EVENT_START = 0;
 	final private static int EVENT_END = 1;
 	final private static int EVENT_CANCEL = 2;