docs: clarify uplink polling

[shorgi]

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: 9c8c0f485ba06433bc159adcc78cf9fae04bd88b

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[netlify[bot]]

✅ Deploy Preview for apollo-federation-docs ready!

Name	Link
🔨 Latest commit	9c8c0f485ba06433bc159adcc78cf9fae04bd88b
🔍 Latest deploy log	https://app.netlify.com/sites/apollo-federation-docs/deploys/66c6cf89dcf03b00084abb0e
😎 Deploy Preview	https://deploy-preview-3126--apollo-federation-docs.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[codesandbox-ci[bot]]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.