[Docs] Remove some unnecessary Twitter references/examples

[patrickhlauke]

Description

Remove some unnecessary Twitter references/examples

Motivation & Context

Unnecessarily dated, and not the best reputation in recent years.

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-{your_pr_number}--twbs-bootstrap.netlify.app/

Related issues

[patrickhlauke]

I'd actually suggest going much further (removing links to @mdo, @fat, @getbootstrap), but for now this is a start