textproc/ruby-review: update to 5.6.0

5.6.0 (2022-10-28)

New Features

* IDGXMLBuilder: support imgmath math_format in //texequation and @<m> (#1829)
* LATEXBuilder: use reviewicon macro instead of reviewincludegraphics in
  @<icon> (#1838)
* trim spaces before/after characters in ruby text (#1839)

Breaking Changes

* LATEXBuilder: use MEMO, NOTICE, CAUTION or other headers instead of ■メモ.
  If you want to use older headers, add ■メモ in locale.yml. (#1856)

Others

* update documents format.md and format.ja.md (#1860)

(taca)