Fix some grammar and typos in comments and docs

Michael Paquier <michael@paquier.xyz>

Commit: 8a15e735be00f156a7227741c0ce88702e6de099
Author: Michael Paquier <michael@paquier.xyz>
Date: 2020-11-02T06:14:41Z
Releases: 14.0
Fix some grammar and typos in comments and docs

The documentation fixes are backpatched down to where they apply.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20201031020801.GD3080@telsasoft.com
Backpatch-through: 9.6

Files

Documentation touched

Discussion