refactor(docs-app): move `bold` directive out of the app controller file

public/_includes/_scripts-include.jade

@@ -18,6 +18,7 @@ script(src="/resources/js/site.js")
 script(src="/resources/js/controllers/app-controller.js")
 script(src="/resources/js/directives/cheatsheet.js")
 script(src="/resources/js/directives/bio.js")
+script(src="/resources/js/directives/bold.js")
 script(src="/resources/js/directives/code.js")
 script(src="/resources/js/directives/code-tabs.js")
 script(src="/resources/js/directives/code-pane.js")

public/resources/js/controllers/app-controller.js

@@ -3,27 +3,6 @@
  *
  */
 
-angularIO.directive('bold', function ($timeout) {
-  return {
-    scope: { bold: '=bold' },
-    link:  postLink
-  };
-  function postLink (scope, element) {
-    var bold = typeof scope.bold === 'string'
-        ? [ scope.bold ]
-        : scope.bold;
-    $timeout(function () {
-      var html = element.html();
-      angular.forEach(bold, function (bold) {
-        html = html.replace(new RegExp(bold.replace(/([.*+?^=!:${}()|\[\]\/\\])/g, "\\$1"), 'g'), '<b>$&</b>');
-      });
-      html = html.replace(/\n/g, '<br>');
-      html = html.replace(/ /g, '&nbsp;');
-      element.html(html);
-    });
-  }
-});
-
 angularIO.controller('AppCtrl', ['$mdDialog', '$timeout', '$http', '$sce', function ($mdDialog, $timeout, $http, $sce) {
   var vm = this;
 

public/resources/js/directives/bold.js

@@ -0,0 +1,20 @@
+angularIO.directive('bold', function ($timeout) {
+  return {
+    scope: { bold: '=bold' },
+    link:  postLink
+  };
+  function postLink (scope, element) {
+    var bold = typeof scope.bold === 'string'
+        ? [ scope.bold ]
+        : scope.bold;
+    $timeout(function () {
+      var html = element.html();
+      angular.forEach(bold, function (bold) {
+        html = html.replace(new RegExp(bold.replace(/([.*+?^=!:${}()|\[\]\/\\])/g, "\\$1"), 'g'), '<b>$&</b>');
+      });
+      html = html.replace(/\n/g, '<br>');
+      html = html.replace(/ /g, '&nbsp;');
+      element.html(html);
+    });
+  }
+});