CHANGES: apply same markup style to older CHANGES logged entries…

[jimklimov]

…fix a few typos

Cosmetics:

• line-wrap to fit in 80-wide terminal/editor
• use backticks for computer-meaningful names and patterns
• start all entries with capitals
• separate known authors with double-dash

Wondered about tracking down relevant issue/PR numbers to help see more context when troubleshooting, but so far had no time for that enhancement.

[jimklimov]

Spellchecker issue addressed in #652