docs: Add GitHub icon to the top right of the document

[kangju2000]

Add a GitHub icon to the upper right corner of the document for quick access to the repository.

[AS-IS]

• The document lacks a direct link to the GitHub repository
• Users have to manually navigate to the GitHub page

[TO-BE]

• A GitHub icon is added to the top right corner of the document
• Clicking the icon will directly link users to the associated GitHub repository