doc: Various typo/grammar fixes

Kevin Grittner <kgrittn@postgresql.org>

Commit: 9c4b7ed13da24cdb2f977547546bb6be437d1974
Author: Kevin Grittner <kgrittn@postgresql.org>
Date: 2014-08-30T16:04:12Z
Releases: 9.2.10
doc: Various typo/grammar fixes

Errors detected using Topy (https://github.com/intgr/topy), all
changes verified by hand and some manual tweaks added.

Marti Raudsepp

Individual changes backpatched, where applicable, as far as 9.0.

Files