(docs) Upgrade to Prettier 2.0

[tesseralis]

Overview

Upgrade to Prettier 2.0 and reformat all files that use it.

Motivation

The new version of Prettier fixes a bug that's causing nested markdown in MDX to fail: #21743. This leads to awkwardly formatted Markdown in a couple of places (paragraphs being hard-wrapped instead of soft-wrapped, requiring <a> tags instead of using markdown notation).

[github-actions]

Hiya!

This issue has gone quiet. Spooky quiet. 👻

We get a lot of issues, so we currently close issues after 30 days of inactivity. It’s been at least 20 days since the last update here.
If we missed this issue or if you want to keep it open, please reply here. You can also add the label "not stale" to keep this issue open!
As a friendly reminder: the best way to see this issue, or any other, fixed is to open a Pull Request. Check out gatsby.dev/contribute for more information about opening PRs, triaging issues, and contributing!

Thanks for being a part of the Gatsby community! 💪💜