Fix closing <size> tag

Thanks to Shane Prendergast for letting us know :)

sections/notes.md

@@ -39,7 +39,7 @@ Attachments are included, but comments are kept separate at `/notes/#{id}/commen
       <id type="integer">2</id>
       <url>https://example.highrisehq.com/files/2</url>
       <name>document.txt</name>
-      <size type="integer">8837</name>
+      <size type="integer">8837</size>
     </attachment>
   </attachments>
 </note>