Log Message:
Update ruby-redcarpet to 3.1.1.

3.1.1

This release of Redcarpet is meant to address a serious bug when rendering
text that contains headings and contains all the prior enhancements of
Redcarpet 3.1.0. For more information about Redcarpet 3.1.0, please see the
release notes

* Bug fixes

  - Fix a crash when rendering text that contained an anchor.

3.1.0

It's been a long time since since we've released any version of Redcarpet but
we are happy to announce the release of the version 3.1.0. Over 100 commits
have been added since 3.0.0 with some new exciting features.

* New features

  - Footnotes
  - GitHub style anchors
  - The :quote option

* Bug fixes

  - Fix code blocks' classes when using Google code prettify #314
  - Follow the standard to detect when new paragraph is outside last item #111
  - Make ordered lists preceded by paragraph parsed with :lax_spacing #311
  - Allow using tabs between a reference's colon and its link #337