Fix Ok button Text of Save and Export Dialog (#876)

to "Save" (also changes to "Save & Quit" when needed) and "Export"

src/Main.gd

@@ -343,6 +343,7 @@ func _on_QuitAndSaveDialog_custom_action(action: String) -> void:
 
 func _on_QuitAndSaveDialog_confirmed() -> void:
 	is_quitting_on_save = true
+	Global.save_sprites_dialog.get_ok().text = "Save & Exit"
 	Global.save_sprites_dialog.popup_centered()
 	quit_dialog.hide()
 	Global.dialog_open(true)

src/UI/Dialogs/ExportDialog.gd

@@ -255,6 +255,7 @@ func set_export_progress_bar(value: float) -> void:
 
 
 func _on_ExportDialog_about_to_show() -> void:
+	get_ok().text = "Export"
 	Global.canvas.selection.transform_content_confirm()
 	var project: Project = Global.current_project
 	# If we're on HTML5, don't let the user change the directory path

src/UI/TopMenuContainer/TopMenuContainer.gd

@@ -404,6 +404,7 @@ func _save_project_file_as() -> void:
 		save_dialog.popup_centered()
 		save_filename.text = Global.current_project.name
 	else:
+		Global.save_sprites_dialog.get_ok().text = "Save"
 		Global.save_sprites_dialog.popup_centered()
 		yield(get_tree(), "idle_frame")
 		yield(get_tree(), "idle_frame")