Extend example of JOIN results for completeness

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/10/static/queries-table-expressions.html
Description:

Hi

The section:
https://www.postgresql.org/docs/10/static/queries-table-expressions.html#QUERIES-FROM
shows result of INNER, LEFT and RIGHT joins.

That worth nothing to put results of FULL join for completeness
but would really informative.