Feature summary (what you would like to be able to do and where):
For older installations, this change is almost meaningless, since the main categories have already been created, but for new ones, it can be useful. Instead of plain text that cannot be bulk changed, insert a pre-made template or interface message that could be changed and would change in all categories at once.
This will save you the trouble of difficultly changing category descriptions on small wikis where there are no bots.
Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
For small wikis that don't have bots or bot guides, it's very difficult to change the text in all categories at once.
Benefits (why should this be implemented?):
Simplify support for extension