Update a11y-basics.md (vuejs#439)

Author: Jinjiang

src/guide/a11y-basics.md

@@ -40,7 +40,7 @@ To hide the link unless it is focused, you can add the following style:
 }
 ```
 
-Once a user changes route, bring focus back to the skip link. This can be achieved by calling focus to the `ref` provided above:
+Once a user changes route, bring focus back to the skip link. This can be achieved by calling focus to the `ref` provided below:
 
 ``` vue
 <script>
@@ -105,7 +105,7 @@ Landmarks provide programmatic access to sections within an application. Users w
 | nav             | role="navigation"                                                 | Collection of links suitable for use when navigating the document or related documents |
 | main            | role="main"                                                       | The main or central content of the document.                                           |
 | footer          | role="contentinfo"                                                | Information about the parent document: footnotes/copyrights/links to privacy statement |
-| aside           | role="complementary"                                              | Supports the main content, yet is separate and meaningful on its own content            |
+| aside           | role="complementary"                                              | Supports the main content, yet is separated and meaningful on its own content            |
 | _Not available_ | role="search"                                                     | This section contains the search functionality for the application                     |
 | form            | role="form"                                                       | Collection of form-associated elements                                                 |
 | section         | role="region"  | Content that is relevant and that users will likely want to navigate to. Label must be provided for this element                |