fix: add navbar hover bg variables (#41316)

[Sanchay117]

Description

This PR adds two missing SCSS variables for navbar link background colors on hover:

• $navbar-light-hover-bg
• $navbar-dark-hover-bg

These variables allow theme authors to customize the background color on hover for light and dark navbars, similar to the already-existing *-hover-color variables.

Motivation & Context

Currently, Bootstrap provides navbar-light-hover-color and navbar-dark-hover-color but lacks corresponding background color variables. This limits customization options and makes it difficult to apply consistent theming via variables. This PR resolves issue #41316.

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-41372--twbs-bootstrap.netlify.app/

Related issues

Closes #41316

[julien-deramond]

Thanks for the PR! That said, we can't add new Sass variables unless they're actually used somewhere in the codebase—this ensures that any overridden values will take effect.

Also, we haven't yet reviewed the related issue to decide whether these two variables should be included at all. So for now, I'll go ahead and close this PR while we wait on that decision.

[Sanchay117]

Alright, thanks for the info!