Bump Ace from 1.4.12 to 1.13.1

See https://github.com/ajaxorg/ace/blob/master/CHANGELOG.md for the
changes. There are many, mostly bug fixes.

Tested manually, including changing all the settings in the settings
window and verifying they worked.

Change-Id: I54c6c788be5838b0a4b000ebafc36a3a30c15f21
Reviewed-on: https://fuchsia-review.googlesource.com/c/fidlbolt/+/761225
Reviewed-by: Matt Hamrick <mjhamrick@google.com>
diff --git a/frontend/src/ace-modes.js b/frontend/src/ace-modes.js
index 1641f80..36b3151 100644
--- a/frontend/src/ace-modes.js
+++ b/frontend/src/ace-modes.js
@@ -2,7 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-ace.define('ace/mode/error', function(require, exports, module) {
+// TODO(fxbug.dev/115431): Bundle the ace editor with webpack.
+ace.config.set(
+  'basePath',
+  // This version must match the one in the index.html template.
+  'https://cdnjs.cloudflare.com/ajax/libs/ace/1.13.1'
+);
+
+ace.define('ace/mode/error', function (require, exports, module) {
   const TextMode = require('ace/mode/text').Mode;
   const TextHighlightRules = require('ace/mode/text_highlight_rules')
     .TextHighlightRules;
diff --git a/frontend/src/index.html b/frontend/src/index.html
index 51856e1..9fa539e 100644
--- a/frontend/src/index.html
+++ b/frontend/src/index.html
@@ -10,6 +10,6 @@
       <div class="lds-ellipsis"><div></div><div></div><div></div><div></div></div>
     </div>
     <div id="Elm"></div>
-    <script src="https://cdnjs.cloudflare.com/ajax/libs/ace/1.4.12/ace.js"></script>
+    <script src="https://cdnjs.cloudflare.com/ajax/libs/ace/1.13.1/ace.min.js"></script>
   </body>
 </html>