fix(ansi): render subsequent paragraphs in list items on new lines

[troclaux]

Summary

When a list item contains multiple paragraphs (loose list syntax), glamour concatenated them without any separator, producing broken output like:

• Here's the second list item.I need to add another paragraph below the second list item.

The KindParagraph handler skipped all paragraphs inside a KindListItem by returning Element{}. Only the first paragraph should be skipped (it's rendered inline as the list item text). Subsequent paragraphs need a newline before them.

Before:

  • This is the first list item.
  • Here's the second list item.I need to add another paragraph below the second list item.
  • And here's the third list item.

After:

  • This is the first list item.
  • Here's the second list item.
  I need to add another paragraph below the second list item.
  • And here's the third list item.

Changes

• ansi/elements.go: check node.PreviousSibling() == nil in the KindParagraph / KindListItem branch; only skip the first paragraph, return Element{Entering: "\n"} for subsequent ones
• testdata/issues/167.md: regression test input
• ansi/testdata/TestRendererIssues/167.golden: expected golden output

Testing

go test ./... passes.

Fixes #167