publishing-libraries docs: Changesets configuration [#9324] (#9325)
### Description
- Fixes #9324
The minimum changed need to make the recommended publishing script work
is to set Changesets' `commit` option[^1] to true.
- Also adds a note about how to publish public packages. Changesets'
default configuration is for private packages.
### Testing Instructions
1. Follow https://turbo.build/repo/docs/guides/publishing-libraries.
2. Confirm that the `publish-packages` script does not work to publish
packages.
3. Make this PR's changes.
4. Confirm that the script now works.
[^1]:
https://github.com/changesets/changesets/blob/7323704dff6e76f488370db384579b86c95c866f/docs/config-file-options.md?plain=1#L19
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Co-authored-by: Anthony Shew <anthony.shew@vercel.com>