Mixed ordered and unordered list hierarchies should indent consistently

[srichy]

Summary

Mixed nested ordered and unordered lists causes indentation prefixes to get dropped in some cases.

Details

Input like this (but starting in the first column; using CODE blocks here):

- This is a top-level bulleted list
  - This is second-level bulleted list
  - Second of the second
    1. This is ordered and second-order nested
    1. Second entry of same

should render like:

* This is a top-level bulleted list
  * This is second-level bulleted list
  * Second of the second
    1. This is ordered and second-order nested
    2. Second entry of same

given formatting options unorderedListMarker: .star, orderedListNumerals:.incrementing(start: 1), and emphasisMarker: .underline.

However, before this change, they render like:

* This is a top-level bulleted list
  * This is second-level bulleted list
  * Second of the second
  1. This is ordered and second-order nested
  2. Second entry of same

in which the prefix is not generated for the ordered list. The dump of the tree is correct, however:

    Document
    └─ UnorderedList
       └─ ListItem
          ├─ Paragraph
          │  └─ Text "This is a top-level bulleted list"
          └─ UnorderedList
             ├─ ListItem
             │  └─ Paragraph
             │     └─ Text "This is second-level bulleted list"
             └─ ListItem
                ├─ Paragraph
                │  └─ Text "Second of the second"
                └─ OrderedList
                   ├─ ListItem
                   │  └─ Paragraph
                   │     └─ Text "This is ordered and second-order nested"
                   └─ ListItem
                      └─ Paragraph
                         └─ Text "Second entry of same"

The above AST shows that the OrderedList is a child of the ListItem and not of the UnorderedList, so it should be indented accordingly when rendered.

Dependencies

None

Testing

I sanity tested with the above examples and ran on some other markdown to verify that the output seems sane.