marker bottom description area slot has been added

[AbdullahAgsar]

i needed a bottom description area for every months. so i do added a new slot for this my problem.

like this:

[Jasenkoo]

You can use the action-extra slot for this context. I will not merge this PR

[AbdullahAgsar]

@Jasenkoo Hello, unfortunately, I cannot use the "action-extra" field. I need an area where I can add descriptions separately for each month. In the system where we use the package, in some cases, we list 24 months, and fields like "action-extra" apply to the entire calendar. In a calendar with 24 months listed, it is not possible to add all important dates in one field. As I have seen from the package documentation and source code, there is no field that fully meets my needs.