ruby-kramdown: update to 2.3.2.

## kramdown 2.3.2 released

This release brings various bug fixes.

## Changes

* 2 minor change:

  - Make codespan delimiter available for converters
  - Make first list item marker available for converters

* 1 bug fix:

  - Fixed handling of top-level text elements when converting from HTML

* 1 other change:

  - Enhanced documentation for "forbidden_inline_options" configuration option

(fcambus)