doc: Clarify description of VALUES command

Greg Smith
Minor docs wordsmithing.

Swap the order of a couple of phrases to clarify what the adjective
"subsequent" applies to.

Joshua Tolley
Correct the documentation of pg_rewrite.ev_attr.

It claimed the value was always zero; it is really always -1.

Per report from Hari Babu
Merge branch 'master' into filter
Merge branch 'filter' into within_group
No moar magickz