spoiler-block-indent-collapse

The first content line establishes the base indentation; that many spaces are stripped from all content lines

§4.15

Input

^^^
  > qa
  > qb
^^^

Output AST

- type: SpoilerBlock
  children:
    - type: QuoteBlock
      children:
        - type: Paragraph
          children:
            - type: Text
              value: qaqb