I want to allow for the definition of admonitions in portable text documents in Sanity v3.
An admonition is a collection of text that exists separately from the main flow of the content. Its purpose is to add information about the topic by drawing the readers attention to this information is a specific context. For instance, Asciidoc defines admonitions of type "Note," "Tip," "Important," "Caution," and "Warning." Sanity's own documentation site uses admonitions like "Need help?" and "Gotcha." Publishers like Pearson permit authors to define their own, which enabled me to use the "Ghosts of Versions Past" admonition in my book "Django Unleashed."
Content authors therefore need the flexibility to define the type of an admonition. The actual admonition will be inline to existing content, but reference an admonition type.
While the admonition is separate from the main flow of content, it should be easy to adjust the content and type of an admonition when working within Sanity to ensure a productive writing experience.
This MVE explores how to achieve this in Sanity. It is for demonstration purposes and is not intended to be deployed, forked, or used in production. You use this code at your own risk.