updated Back to top/bottom across all pages

[Nikhilrsingh]

Description

Updated about.html | about.css | about.js | convert.html | customize.html | faq.html | scale.html | index.html for back to top/bottom

Type of change

• Bug fix
• Improvement
• Documentation update

How Has This Been Tested?

Tested locally all working fine

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code where necessary
• I have made corresponding changes to the documentation

[github-actions]

Thanks for creating a PR for your Issue! ☺️

We'll review it as soon as possible.
In the meantime, please double-check the file changes and ensure that all commits are accurate.

If there are any unresolved review comments, feel free to resolve them. 🙌🏼

[Nikhilrsingh]

@supriya46788 maam Please review this PR, and add the appropriate labels.