fix: updating WordPress fullstack instructions

[harrykimpel]

Give us some context

• What problems does this PR solve?

• fixes parts of the instructions
  

• Add any context that will help us review your changes such as testing notes,
  links to related docs, screenshots, etc.
• If your issue relates to an existing GitHub issue, please link to it.

[github-actions]

Hi @harrykimpel 👋

Thanks for your pull request! Your PR is in a queue, and a writer will take a look soon. We generally publish small edits within one business day, and larger edits within three days.

Please ensure the propsed changes look good by building it first in your local environment. Refer to this contribution guide to get the site up and running in your local.

If you really require a preview url, reach out to one of the writers and they will generate one for you.

[PallaviWrite]

lgtm