Docs(SplitPageLayout): add PageLayout props to .docs.json

[francinelucca]

Closes https://github.com/github/primer/issues/3575

The SplitPageLayout.Pane component is a PageLayout.Pane under the hood and can therefore accept any props that PageLayout.Pane accepts. This PR updates the documentation to reflect some missing props, including aria-label, aria-labelledby.

This PR also adds aria-label to Panes inSplitPageLayout stories so that it can be displayed when the content overflows.

Changelog

New

• Adds aria-label, aria-labelledby props to SplitPageLayout.Pane docs.json file
• Updates type and description of width prop in SplitPageLayout.Pane docs.json file to more closely match with PageLayout.Pane docs
• Adds aria-label prop to Panes in SplitPageLayout stories

Rollout strategy

• [] Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why

Docs only update

Testing & Reviewing

Navigate to deployed SplitPageLayout.Pane story and resize browser so that the pane overflows, verify in the DOM that aria-label prop is added, along with tabIndex=0 and role='region'

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[changeset-bot]

⚠️ No Changeset found

Latest commit: 0617eb8

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[github-actions]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	97.61 KB (0%)
packages/react/dist/browser.umd.js	97.79 KB (0%)