Bump highlightjs

Gemfile

@@ -101,7 +101,7 @@ 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",                         "9.7.0"
+  gem "rails-assets-highlightjs",                         "9.9.0"
 
   gem "rails-assets-backbone",                            "1.3.3"
   gem "rails-assets-bootstrap-markdown",                  "2.10.0"

Gemfile.lock

@@ -535,7 +535,7 @@ GEM
     rails-assets-emojione (2.0.1)
     rails-assets-favico.js (0.3.10)
     rails-assets-fine-uploader (5.13.0)
-    rails-assets-highlightjs (9.7.0)
+    rails-assets-highlightjs (9.9.0)
     rails-assets-jasmine (2.4.1)
     rails-assets-jasmine-ajax (3.2.0)
       rails-assets-jasmine (~> 2)
@@ -876,7 +876,7 @@ DEPENDENCIES
   rails-assets-corejs-typeahead (= 1.1.1)!
   rails-assets-diaspora_jsxc (= 0.1.5.develop.7)!
   rails-assets-fine-uploader (= 5.13.0)!
-  rails-assets-highlightjs (= 9.7.0)!
+  rails-assets-highlightjs (= 9.9.0)!
   rails-assets-jasmine-ajax (= 3.2.0)!
   rails-assets-jquery (= 2.2.4)!
   rails-assets-jquery-placeholder (= 2.3.1)!