Update Vale configuration example

[jdbaldry]

I need to also update the steps to tell a user to run vale sync

• I've used a relevant pull request (PR) title.
• I've added a link to any relevant issues in the PR description.
• I've checked my changes on the deploy preview and they look good.
• I've added an entry to the What's new page (only required for notable changes).

[github-actions]

💻 Deploy preview available: https://deploy-preview-writers-toolkit-951-zb444pucvq-vp.a.run.app/docs/writers-toolkit/

[jdbaldry]

Suggested change

	Replace _`<PATH TO WRITERS TOOLKIT REPOSITORY>`_ with the full path to your checkout of the Writer's Toolkit repository.
	Replace _`<PATH TO WRITERS TOOLKIT REPOSITORY>`_ with the full path to your checkout of the Writers' Toolkit repository.

[clayton-cornell]

I had to do a <PATH>/vale --config='<PATH>/vale.ini sync to get vale working with this updated vale.ini. (I included because vale binary and vale.ini are not in my system path :-P )