Fix: Clean up malformed cross-references and other sphinx warnings

[mbenavidez-amd]

Motivation

Clean up and resolve recurring sphinx build warnings driven by malformed or incomplete cross-references.

Technical Details

This pull request makes several documentation improvements and fixes to the customer acceptance guide. The main changes include updating and correcting internal and external links, improving formatting for consistency, and enhancing readability by removing unnecessary formatting artifacts.

Documentation Link and Formatting Improvements:

• Updated several internal documentation links in system-validation.md to use correct or more robust references.
• Fixed the external link to the "TransferBench how to guide" in related-documentation.md to point to the correct URL.

Formatting and Readability Enhancements:

• Clarified example JSON output by replacing ellipsis with a comment and removing non-breaking spaces in result explanations.

Documentation Build Configuration:

• Enabled up to level 4 heading anchors in the Sphinx configuration to improve navigation within generated documentation.

Test Plan

Ran on local builds to ensure changes removed sphinx build warnings.

Test Result

Verified warnings were reesolved in local sphinx builds.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[rzimmer512]

Reviewed. No concerns.