update index.html

[L200190221]

pemberian link a href ke about.html pada navbar brand clas fab fa-osi

Description

Include a summary of the change and relevant motivation/context. List any dependencies that are required for this change.

Fixes # [ISSUE]

Type of Change:

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• Code
• Quality Assurance
• User Interface
• Outreach
• Documentation

How Has This Been Tested?

Describe the tests you ran to verify your changes. Provide instructions or GIFs so we can reproduce. List any relevant details for your test.

Checklist:

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• My PR follows the style guidelines of this project
• I have performed a self-review of my own code or materials
• I have commented my code or provided relevant documentation, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation