Describe the PR

fixes #2538

• If footVariant, footRowVariant, footClass and footTrClass aren't specified, fall back to the equivalent head props.
• If the foot() or foot(*) slot isn't defined, fall back to the equivalent head slot
  • Add some documentation to how this fallback works, as I misread the BSV docs and implemented it incorrectly the first time
• Add unit tests for this and related behavior

Small replication

See unit tests in this PR

PR checklist

What kind of change does this PR introduce? (check at least one)

• Bugfix 🐛 - fix(...)
• Feature - feat(...)
• ARIA accessibility - fix(...)
• Documentation update - docs(...)
• Other (please describe)

The PR fulfills these requirements:

• Pull request title and all commits follow the Conventional Commits convention or has an override in this pull request body This is very important, as the CHANGELOG is generated from these messages, and determines the next version type. Pull requests that do not follow conventional commits or do not have an override will be denied