Div fences immediately following lists (no newline) are swallowed by the list

[zkamvar]

I noticed that this div was causing a build to fail at the validation step with this diagnostic:

── Validating Fenced Divs ──────────────────────────────────────────────────────
Error: Error in .x[[1]] : subscript out of bounds
Calls: <Anonymous> ... get_linestart -> get_pos -> gsub -> is.factor -> <Anonymous>
Execution halted

It turns out that the closing fence for this div was being interpreted as part of the previous list item:

https://github.com/MCMaurer/Rewrite-R-ecology-lesson/blob/b23e42e4a876ce4aff65cf38ad98753f72719eba/episodes/01-visualizing-ggplot.Rmd#L401-L412

Here's a simplified use case:

tmp <- tempfile()
writeLines("text\n\n::: callout\n- list item\n  - list item 2\n:::\n\n text", tmp)
ep <- pegboard::Episode$new(tmp)
ep$show()
#> text
#> 
#> ::: callout
#> 
#> - list item
#>   - list item 2
#>     :::
#> 
#> text
ep$label_divs()$get_divs()
#> $`div-1-callout`
#> {xml_nodeset (0)}

^{Created on 2022-03-14 by the reprex package (v2.0.1)}