doc has self referential definition

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/9.5/static/sql-select.html
Description:

https://www.postgresql.org/docs/9.6/static/sql-select.html

The last line for <from_item> breaks the group.  There should be something
like:

<from_item>
   <join_from>
   <simple_from>

(with better naming).

Thanks for Postgresql.

Rob