[docs] Update explainer around reducing-bundle-size

[smyrick]

I wrote this from an internal call. It was good insights that should be on our public docs

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: 9eed952de25303ba2b172ece89eb9c69cc4b5604

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-client-docs ready!

Name	Link
🔨 Latest commit	9eed952de25303ba2b172ece89eb9c69cc4b5604
🔍 Latest deploy log	https://app.netlify.com/sites/apollo-client-docs/deploys/663be3c7e03d10000867763f
😎 Deploy Preview	https://deploy-preview-11791--apollo-client-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.

[jerelmiller]

@Meschreiber when you get a chance, I'd love for you to take a look 🙂

[phryneas]

Uh, it seems I can't push to this branch. Could you please run npm run format locally?

[phryneas]

Thank you!