Docs: clarify the subject of the About page

[louismaximepiton]

Description

Clarify the h1 heading of the page.

Motivation & Context

It'll bring more context for AT users within the page.
After an accessibility audit of our site (based on Bootstrap), just committing the patch upstream.

Type of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (non-breaking change)
• Breaking change (fix or feature that would change existing functionality)

Checklist

• I have read the contributing guidelines
• My code follows the code style of the project (using npm run lint)
• My change introduces changes to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed

Live previews

• https://deploy-preview-40762--twbs-bootstrap.netlify.app/docs/5.3/about/overview

Related issues

Orange-OpenSource/Orange-Boosted-Bootstrap#2667 with issue 4.2.

[anandfresh]

LGTM

[patrickhlauke]

I'd say an about page on a particular project/site is implicitly "about" that project/site, but sure, no harm in being specific