Improve next/future/image Migration docs

[MaedahBatool]

The comparison table for migration to next/future/image looks odd layout-wise. The issue was brought up via this Slack thread.

This PR makes this improvement.

New implementation

Bug

• [ ] Related issues linked using fixes #number
• [ ] Integration tests added
• [ ] Errors have helpful link attached, see 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
• [ ] Integration tests added
• [ ] Documentation added
• [ ] Telemetry added. In case of a feature if it's used or not.
• [ ] Errors have helpful link attached, see contributing.md

Documentation / Examples

• [ ] Make sure the linting passes by running pnpm lint
• [ ] The examples guidelines are followed from our contributing doc