Support todos in Dialogic Timeline files

[Taylor-Mattison]

I am writing a visual novel using the Dialogic plugin, which stores its dialog in plaintext files with a .dtl extension. Please consider adding support for todos in these .dtl files by simply updating the plugin.gd script's get_dir_contents() function by simply adding .dtl to your list of scanned files.

			or file_name.ends_with(".c") or file_name.ends_with(".cpp") or file_name.ends_with(".h") \
			or file_name.ends_with(".dtl") \
			or ((file_name.ends_with(".tscn") and _dockUI.builtin_enabled)):
				scripts.append(dir.get_current_dir().path_join(file_name))```