caption-quoteblock

A ^ line after a QuoteBlock sets the caption field, as for every other captionable block

§6.2

Input

> To be, or not to be.
^ William Shakespeare

Output AST

- type: QuoteBlock
  children:
    - type: Paragraph
      children:
        - type: Text
          value: To be, or not to be.
  caption:
    - type: Text
      value: William Shakespeare