Docs: enhance colors description table

[julien-deramond]

Description

This PR suggests to display slightly differently the colors in the second part of the table in https://getbootstrap.com/docs/5.3/customize/color/#colors so that:

• --bs-xxx, --bs-xxx-rgb and --bs-xxx-bg-subtle are displayed as background colors
• --bs-xxx-border-subtle is displayed as a big border
• --bs-xxx-text is displayed as an actual text

Motivation & Context

We struggled to understand this table with @louismaximepiton when he was trying to find a dark/black text color for another PR.

When you have such a goal in mind and that you can directly in https://getbootstrap.com/docs/5.3/customize/color/#colors, there's --bs-dark-text and the text is displayed as white. IMO it's very hard to understand.

Type of changes

• Enhancement

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

Live previews

• https://deploy-preview-37811--twbs-bootstrap.netlify.app/docs/5.3/customize/color/#colors

[mdo]

Oh this looks great! Just reviewed in my phone, will check more closely on laptop later today.

[mdo]

Beautiful!