The @rouge@ gem "claims to follow":https://github.com/rouge-ruby/rouge/blob/master/CHANGELOG.md#changelog Semantic Versioning 2.0.0. As such, most releases of the gem in the past bumped the minor version.

I think it is not necessary to bump every minor release in our @Gemfile@, thereby forcing users on older Redmine releases to stay on an older rouge version unnecessarily.

As such, I think we should relax the @rouge@ dependency to something like

gem "rouge", "~> 3.28"

As with this change, people might have different languages available (as different @rouge@ versions support different languages). Accordingly, I propose we also dynamically generate the list of highlighted languages (currently in @public/help/code_highlighting_languages.html@) with a controller action.