corrected /examples/github-pages readme (#43766)

`branch` is the correct subheading direction; the `source` subheading represents `deploying from a branch` or from a `github action`



## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have a helpful link attached, see [`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] [e2e](https://github.com/vercel/next.js/blob/canary/contributing/core/testing.md#writing-tests-for-nextjs) tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see [`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)

## Documentation / Examples

- [ ] Make sure the linting passes by running `pnpm build && pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)

examples/github-pages/README.md

@@ -22,7 +22,7 @@ pnpm create next-app --example github-pages nextjs-github-pages
 1.  Edit `next.config.js` to match your GitHub repository name.
 1.  Push the starter code to the `main` branch.
 1.  Run the `deploy` script (e.g. `npm run deploy`) to create the `gh-pages` branch.
-1.  On GitHub, go to **Settings** > **Pages** > **Source**, and choose `gh-pages` as the branch with the `/root` folder. Hit **Save**.
+1.  On GitHub, go to **Settings** > **Pages** > **Branch**, and choose `gh-pages` as the branch with the `/root` folder. Hit **Save**.
 1.  Make a change.
 1.  Run the `deploy` script again to push the changes to GitHub Pages.