chore: filter React Fragments

[petermikitsh]

Sample code:

export const Fragment = () => {
  return (
    <>
      <Button onClick={action('clicked')}>Button in Fragment</Button>
    </>
  );
};

Before:

After:

📦 Published PR as canary version: 1.2.38-canary.106.1391.0

:sparkles: Test out this PR locally via: ```sh npm install storybook-addon-react-docgen@1.2.38-canary.106.1391.0 # or yarn add storybook-addon-react-docgen@1.2.38-canary.106.1391.0 ```