message: docs: Add notes about prettier to repo README
  Adds some simple notes about how [prettier](https://prettier.io/) fits
  into our repository's infrastructure.
diff: @@ -186,6 +186,28 @@ Then:
  - `npm run start:tinylicious`
  - Browse to <http://localhost:8080,> copy the full URL you're redirected to, and open in a second window to collaborate
  +## Tools
  +
  +### Prettier
  +
  +This repository uses [prettier](https://prettier.io/) as its code formatter.
  +Right now, this is implemented on a per-package basis, with a [shared base configuration](./common/build/build-common/prettier.config.cjs).
  +
  +To run `prettier` on your code, run `npm run format` from the appropriate package or release group.
  +
  +* To run `prettier` with [fluid-build](./build-tools/packages/build-tools/README.md), you can specify "format" via the script argument (e.g. `fluid-build -s format`).
  +
  +To ensure our formatting remains consistent, we run a formatting check as a part of each package's `lint` script.
  +
  +#### VSCode Options
  +
  +Our [workspace configuration](./.vscode/settings.json) specifies `prettier` as the default formatter.
  +Please do not change this.
  +
  +It is not configured to do any formatting automatically, however.
  +This is intentional, to ensure that each developer can work formatting into their workflow as they see fit.
  +If you wish to configure your setup to format on save/paste/etc., please feel free to update your [user preferences](https://code.visualstudio.com/docs/getstarted/settings) to do so.
  +
  ## Contributing
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