Add documentation on how to export variable at runtime with set() and get()

[Shadowblitz16]

Your Godot version:
3.2.3

Issue description:
I am trying to make a JSON resource importer but I'm not sure how to export dynamically created variables
Please add documentation on how to export variable at runtime with set() and get()

URL to the documentation page (if already existing):
https://docs.godotengine.org/en/stable/tutorials/plugins/editor/import_plugins.html

[Calinou]

What do you mean by "exporting a variable at runtime"? Can you describe some possible use cases for this?

[Shadowblitz16]

like so..

func import(source_file, save_path, options, r_platform_variants, r_gen_files):
	var file = File.new()
	var err = file.open(source_file, File.READ)
	if err != OK:
		return err
	
	var dict = json2dict(file.get_as_text())
	
	file.close()
	var resource = parse_dict(Resource.new(), dict)
	resource.property_list_changed_notify()
	return ResourceSaver.save("%s.%s" % [save_path, get_save_extension()], resource)

func parse_dict(resource:Resource, dict:Dictionary)->Resource:
	var properties = resource.get_property_list()
	
	for i in range(properties.size()):
		var k = properties[i].name
		var v = properties[i].value
		if  v is Resource: resource.set(k, parse_dict(resource, v))
		else:              resource.set(k, v)
                # export(resource.get(k))
	return resource