More adding package docs tweaks (#2257)

## Checklist

- [-] I have added
[tests](https://www.cursorless.org/docs/contributing/test-case-recorder/)
- [x] I have updated the
[docs](https://github.com/cursorless-dev/cursorless/tree/main/docs) and
[cheatsheet](https://github.com/cursorless-dev/cursorless/tree/main/cursorless-talon/src/cheatsheet)
- [-] I have not broken the cheatsheet

Author: pokey

docs/contributing/adding-a-new-package.md

@@ -5,10 +5,16 @@ Replace `foo` with your new package name in the instructions below.
 1. `cd packages`
 2. `mkdir foo && cd foo`
 3. `pnpm init`
-4. `code package.json` and update the `description` field
+4. `code package.json` and update the `description` field. If your package is
+   not a library (ie it's an entrypoint), add a `"private": true,` line to your
+   `package.json`.
 5. `pnpm install`
 6. `pnpm -w fix:meta`
-7. If your package is not a library (ie it's an entrypoint), add a `"private": true,` line to your `package.json`, then run another `pnpm -w fix:meta` for good measure.
+
+If your package is not a library, you get a bit less scaffolding for free, so
+you may want to steal some of the scripts, as well as possibly the `main`,
+`types`, and `exports` fields, from one of our library's `package.json`s. The
+`@cursorless/common` package is a decent one to steal from.
 
 For any packages that you need to depend on, you can run