docs: Improve doc formatting and fix linting issues with markdownlint…

[xianshujun]

close #483

What type of PR is this?
This is a docs type PR, as it focuses on improving the formatting and style of the documentation files.

What this PR does / why we need it?
This PR addresses several issues related to the formatting and linting of Markdown files in the documentation site. Specifically:

• Improved Document Formatting:

  • Adjusted heading hierarchy to follow consistent standards.
  • Fixed list formatting issues (e.g., unordered vs. ordered lists).
  • Ensured all links and images are properly formatted.

• Fixed Linting Issues:

  • Used the markdownlint tool to identify and fix style violations.
  • Resolved issues such as missing spaces after headings, incorrect indentation.

These changes improve the overall quality and consistency of the documentation, making it easier for users to read and understand.

Which issue(s) this PR fixes?
This PR resolves the following issue:

• Fixes docs: Optimize document formatting and content in document sites #483: Optimize document formatting and content in document sites.

Additional Notes:

• All changes have been validated using the markdownlint plugin in VSCode.
• Local tests (make test) were run successfully before submitting this PR.

[CLAassistant]

All committers have signed the CLA.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[LinuxSuRen]

LGTM