docs(guide/component): use ctrl instead of this (for consistency)

Closes angular#14215

Author: tkorakas

docs/content/guide/component.ngdoc

@@ -230,27 +230,27 @@ it upwards to the heroList component, which updates the original data.
 
   function EditableFieldController($scope, $element, $attrs) {
     var ctrl = this;
-    this.editMode = false;
+    ctrl.editMode = false;
 
-    this.handleModeChange = function() {
+    ctrl.handleModeChange = function() {
       if (ctrl.editMode) {
         ctrl.onUpdate({value: ctrl.fieldValue});
         ctrl.fieldValueCopy = ctrl.fieldValue;
       }
       ctrl.editMode = !ctrl.editMode;
     };
 
-    this.reset = function() {
+    ctrl.reset = function() {
       ctrl.fieldValue = ctrl.fieldValueCopy;
     };
 
-    this.$onInit = function() {
+    ctrl.$onInit = function() {
       // Make a copy of the initial value to be able to reset it later
-      this.fieldValueCopy = this.fieldValue;
+      ctrl.fieldValueCopy = ctrl.fieldValue;
 
       // Set a default fieldType
-      if (!this.fieldType) {
-        this.fieldType = 'text';
+      if (!ctrl.fieldType) {
+        ctrl.fieldType = 'text';
       }
     };
   }