Event based dialogue handling (#443)

* Event based dialogue handling

* better imo

* typo

* Small script example

new script by NexIsDumb

---------

Co-authored-by: ⍚~Nex <87421482+NexIsDumb@users.noreply.github.com>

source/funkin/backend/scripting/events/dialogue/DialogueNextLineEvent.hx

@@ -0,0 +1,14 @@
+package funkin.backend.scripting.events.dialogue;
+
+/**
+ * CANCEL this event to prevent continuing with the next dialogue.
+ *
+ * **NOTE**: To access the current, past or next lines, use `curLine`, `lastLine` or also `dialogueLines` in the `DialogueCutscene` class (they're globals and can be accessed at any time as long as the Dialogue Cutscene is active)!
+ */
+final class DialogueNextLineEvent extends CancellableEvent
+{
+	/**
+	 * If the dialogue has just been opened.
+	 */
+	public var playFirst:Bool = false;
+}