[DOCS] expessions alowed in UPDATE RETURNING

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Page: https://www.postgresql.org/docs/9.6/static/sql-update.html
Description:

https://www.postgresql.org/docs/current/static/sql-update.html

From the explanation of the "output_expression" clause and, correspondingly,
from the example, it is not clear, whether columns not mentioned nor in the
SET clause nor in the FROM clause are allowed in the RETURNING clause.

In other words, can I use a ststement like this: "UPDATE weather SET temp_lo
= temp_lo+1, temp_hi = temp_lo+15 RETURNING prcp" (look, I did not modified
prcp in this statement).