Fix accessibility issues for Shared Cloud Environment page

[iam4tune]

Pull Request

Intent

The edits and changes were made to fix the accessibility issues from reviewing the page using the Accessibility Insights for Web extension.

Proposed Changes

• SPAG
• Clearer text for images
• Provide additional instructions to aid non-visual users

Changes to Section Headers

Changes to Page URLs

N/A

Related or Fixed Issues

Fixes #1173

Accessibility Checklist

I have ensured all of the following for new or changed content:

• all images have appropriate alt text. Guidelines
• all images with text have sufficient contrast ratio. Checker
• all image text is transcribed or described in body text.
• all technical terms, jargon, and abbreviations are introduced before they are used.

Style Checklist

I have done all of the following:

• searched for other relevant pages and crosslinked from my content to them.
• searched for other relevant pages and crosslinked from them to my content.
• added redirects in mkdocs.yml for any moved headers or pages.
• defined new technical terms, jargon, and abbreviations in the glossary.
• searched for existing technical terms, jargon, and abbreviations in the glossary and added crosslinks to them.
• properly formatted and introduced key branding terms. List here.