Update documentation that setWcStorybookHelpersConfig is needed in preview.js

[wimdeblauwe]

I am just getting started with web components and Storybook. I had a bit of trouble to figure out why the different options of my custom type was not shown in storybook. There was no select, there was an input field.

After I found https://github.com/break-stuff/wc-storybook-helpers/blob/main/demo/lit-app-v8/.storybook/preview.ts I saw that I needed to add this to preview.ts:

import {setWcStorybookHelpersConfig} from "wc-storybook-helpers";

setWcStorybookHelpersConfig({
  hideArgRef: false,
  typeRef: "expandedType",
  renderDefaultValues: false
});

After adding this, Storybook renders the select nicely.