Accessibility fixes

[anjalin14]

Please read and consider what information you want to pass on to people reviewing this PR

Purpose of PR

Type of change:

• Bug fix
• New feature
• Code refactor
• Breaking change
• Documentation update
• Other (please describe)

• Description of the feature
  Update some docs pages that do not comply with accessibility guidelines for missing ALT text (as per Airtable data https://airtable.com/app37pNUyXZSNtgbA/shrrDww8gRjbBYbPk/tblfkGQ6zh9Ovb49k)

• Links to screenshots, design docs, user docs, etc.

• Links to Jira/Fogbugz cases

• Halo effect
  What areas do you know/expect this feature to affect? Do you have any worries about possible breaking points? Write them down here.

• Performance Impact
  Could this PR affect performance? If so, what has been done to measure time taken per frame, memory used, etc.?

• Package requirements
  What Unity Editor version is required/supported? Any other dependancy packages needed?

Checklist for PR maker

• Have you added a backport label? (if needed)
• Have you updated the Changelog? Each package has a CHANGELOG.md file
• Have you added or updated the Documentation to your PR? When you add a new feature, change a property name, or change the behaviour of a feature, it's best practice to include related documentation changes in the same PR

---

Testing status

• Existing or new automation tests - what automation was added, changed
  Put any relevant Yamato links here
• Detailed description of what testing was done, what projects were run
  Tell the reviewers what did you already test, so that they may have a better understanding when reviewing/testing this PR themselves
• What environment did you test on?
  Your Operating System, Platforms you ran on, Graphics APIs and any other relevant info you can think of
• Projects
  Any existing projects ready for testing should be noted here
• Testing checklist

• Built and run editor Locally or Katana
• Built a player Android/iOS (if applicable)
• Run on device Android/iOS (if applicable)
• If new feature has UI, does it match Unity style? (Unity HIG?)
• Tested Undo/Redo + Prefab overrides + Alignment in Preset
• All items have tooltips?

---

Note to guardian

Changeset to use, if extra changesets on top. Any other notes to pass along

Comments to reviewers

Notes for the reviewers you have assigned