docs: properly order words in component name (#2683)

https://vuejs.org/v2/style-guide/#Order-of-words-in-component-names-strongly-recommended

Author: gormonn

src/v2/guide/instance.md

@@ -24,10 +24,10 @@ A Vue application consists of a **root Vue instance** created with `new Vue`, op
 Root Instance
 └─ TodoList
    ├─ TodoItem
-   │  ├─ DeleteTodoButton
-   │  └─ EditTodoButton
+   │  ├─ TodoButtonDelete
+   │  └─ TodoButtonEdit
    └─ TodoListFooter
-      ├─ ClearTodosButton
+      ├─ TodosButtonClear
       └─ TodoListStatistics
 ```