Add clarification to print api on receipt printing

[vctrchu]

Part of https://github.com/Shopify/pos-next-react-native/issues/50918

Background

Explicitly state the native printing capability and non-support for receipt printing.

🎩

https://shopify-dev.ui-extensions-pp9g.victor-chu.us.spin.dev/docs/api/pos-ui-extensions/unstable/apis/print-api

Checklist

• I have 🎩'd these changes
• I have updated relevant documentation

[github-actions]

We detected some changes in packages/*/package.json or packages/*/src, and there are no updates in the .changeset directory. If the changes are user-facing and should cause a version bump, run yarn changeset to track your changes and include them in the next release CHANGELOG. If you are making simple updates to repo configuration, examples, or documentation, you do not need to add a changeset.