Fix Javascript to work with new Haml 5.0 escape behavior

The interpolated Ruby in a Haml :javascript filter now gets HTML escaped, breaking the way it was being used in the shared _head template to pass the set of valid languages and projects.

The fix is to pass it as an HTML dataset instead, and pull that into the Javascript afterwards. I followed the example of railsadminteam/rails_admin#2870

app/views/shared/_head.html.haml

@@ -11,6 +11,7 @@
 
 = javascript_include_tag '/assets/javascripts/i18n'
 = javascript_include_tag '/assets/javascripts/i18n/' + I18n.locale.to_s
+#wikis{:'data-projects' => Wiki::PROJECTS.to_json, :'data-languages' => Wiki::LANGUAGES.to_json}
 :javascript
   I18n.defaultLocale = "#{I18n.default_locale}";
   I18n.locale = "#{I18n.locale}";
@@ -27,8 +28,8 @@
     disableTraining: #{Features.disable_training?}
   }
 
-  WikiProjects = #{Wiki::PROJECTS}
-  WikiLanguages = #{Wiki::LANGUAGES}
+  WikiProjects = document.getElementById("wikis").dataset.projects
+  WikiLanguages = document.getElementById("wikis").dataset.languages
 
   SentryDsn = "#{ENV['sentry_public_dsn']}"
   SalesforceServer = "#{ENV['SF_SERVER']}"