Disable clean-css's advanced optimizations for docs.min.css.

It's causing code highlighting to fail.

Gruntfile.js

@@ -81,7 +81,7 @@ module.exports = function(grunt) {
 
     cssmin: {
       options: {
-        banner: '', // set to empty ; see bellow
+        banner: '', // set to empty; see bellow
         keepSpecialComments: '*', // set to '*' because we already add the banner in sass
         report: 'min'
       },
@@ -90,6 +90,9 @@ module.exports = function(grunt) {
         dest: '<%= meta.distPath %><%= pkg.name %>.min.css'
       },
       docs: {
+        options: {
+          noAdvanced: true  // disable advanced optimizations since it causes code highlighting not to work
+        },
         src: [
           '<%= meta.docsAssetsPath %>css/docs.css',
           '<%= meta.docsAssetsPath %>css/pygments-manni.css'