Update highlight.js

closes #6558

Gemfile

@@ -100,7 +100,7 @@ source "https://rails-assets.org" do
   gem "rails-assets-markdown-it--markdown-it-for-inline", "0.1.1"
   gem "rails-assets-markdown-it-sub",                     "1.0.0"
   gem "rails-assets-markdown-it-sup",                     "1.0.0"
-  gem "rails-assets-highlightjs",                         "8.8.0"
+  gem "rails-assets-highlightjs",                         "8.9.1"
 
   # jQuery plugins
 

Gemfile.lock

@@ -538,7 +538,7 @@ GEM
       rails-assets-jquery.slimscroll (= 1.3.6)
       rails-assets-jquery.ui (= 1.11.4)
     rails-assets-favico.js (0.3.9)
-    rails-assets-highlightjs (8.8.0)
+    rails-assets-highlightjs (8.9.1)
     rails-assets-jakobmattsson--jquery-elastic (1.6.11)
       rails-assets-jquery (>= 1.2.6)
     rails-assets-jasmine (2.3.4)
@@ -832,7 +832,7 @@ DEPENDENCIES
   rack-ssl (= 1.4.1)
   rails (= 4.2.5)
   rails-assets-diaspora_jsxc (~> 0.1.4.alpha, < 0.1.4.develop)!
-  rails-assets-highlightjs (= 8.8.0)!
+  rails-assets-highlightjs (= 8.9.1)!
   rails-assets-jakobmattsson--jquery-elastic (= 1.6.11)!
   rails-assets-jasmine-ajax (= 3.2.0)!
   rails-assets-jeresig--jquery.hotkeys (= 0.2.0)!