v0.21.0

[0.21.0] - 2026-06-20

Added

• no_toc_class config option to customize the class that excludes a heading
  from the TOC (default: no_toc), mirroring the configurable no_toc_section_class.

Changed

• The {% toc %} tag now requires toc: true strictly, matching the toc /
  toc_only / inject_anchors filters. Previously the tag accepted any truthy
  front-matter value. If you relied on a non-true truthy value (e.g. toc: "yes")
  to render the tag, set it to toc: true.

Fixed

• Escape heading ids when interpolating them into href attributes, preventing
  HTML/attribute injection from an author-supplied id containing characters
  such as ".
• De-duplicate headings that share an explicit id: a second id="foo" now
  links to #foo-1 instead of emitting a duplicate #foo fragment. Previously
  only generated ids were de-duplicated.