Text field under list title in manual curated list

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Currently there isn't an option to add an overview under a list title in a manually created curated list with a table of contents. Adding an optional field for text would enable authors to add a description under a list title. For instance, in the OIG we have investigations PDFs under a list title. It would be great to include a blurb about what investigations are, what they involved, etc.

Describe the solution you'd like
What would you like to see added or changed? Why? Include any benefits, challenges, or considerations. This can be short and sweet.

A text field added under a list item in a manually created curated list when a TOC has been created.

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Reference
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No implementation files, entry points, or tests are mentioned in this feature request. Start by finding the Mass.gov project’s manually curated list editor and the rendering path for lists with a table of contents. Done means authors can provide optional text and see it beneath each list title when a TOC is present.