Fix misc typos, mostly in comments.

Heikki Linnakangas <heikki.linnakangas@iki.fi>

Commit: 65976cd86a9bdeec5a5277545e5efa33724102c8
Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: 2018-07-18T13:17:42Z
Releases: 11.0
Fix misc typos, mostly in comments.

A collection of typos I happened to spot while reading code, as well as
grepping for common mistakes.

Backpatch to all supported versions, as applicable, to avoid conflicts
when backporting other commits in the future.

Files

Documentation touched