fix todo list examples

Author: chrisvfritz

src/v2/guide/list.md

@@ -262,7 +262,7 @@ Vue.component('todo-item', {
   template: '\
     <li>\
       {{ title }}\
-      <button v-on:click="$emit('remove')">X</button>\
+      <button v-on:click="$emit(\'remove\')">X</button>\
     </li>\
   ',
   props: ['title']
@@ -309,7 +309,7 @@ Vue.component('todo-item', {
   template: '\
     <li>\
       {{ title }}\
-      <button v-on:click="$emit('remove')">X</button>\
+      <button v-on:click="$emit(\'remove\')">X</button>\
     </li>\
   ',
   props: ['title']