Add hljs html syntax

Author: ryyppy

common/App.re

@@ -18,6 +18,7 @@
   let res = require('../plugins/res-syntax-highlightjs');
   let bash = require('highlight.js/lib/languages/bash');
   let json = require('highlight.js/lib/languages/json');
+  let html = require('highlight.js/lib/languages/xml');
   let ts = require('highlight.js/lib/languages/typescript');
   let text = require('highlight.js/lib/languages/plaintext');
   let diff = require('highlight.js/lib/languages/diff');
@@ -30,6 +31,7 @@
   hljs.registerLanguage('sh', bash);
   hljs.registerLanguage('json', json);
   hljs.registerLanguage('text', text);
+  hljs.registerLanguage('html', html);
   hljs.registerLanguage('diff', diff);
 |};