Feature/issues 14876 add footer content tables docs

[borjajimnz]

Description

Add contentFooter to tables/advanced docs with a brief description regarding the issue discussed in #14876

Functional changes

• Code style has been fixed by running the composer cs command.
• Changes have been tested to not break existing functionality.
• Documentation is up-to-date.

[danharrin]

Thanks for this. I think the developer experience is bad for this feature so I am going to continue to omit it from the documentation. I will think about improving the developer experience in v4 by allowing the user to use a <div> instead of a table element, and add to the documentation if I think it is better.