Add sentence to pre-amble

Incorporate suggestion from dwilson that the one of the document's
goals is to identify off-putting behavior
Clarify that "well actually" is about nitpicking

Incorporate suggestions from dwilson
Add closing paragraph about learning from mistakes.

Incorporate suggestions from dwilson.  "The more you know..."
Wordsmith apology paragraph

Add suggestion from dwilson to change wording to "...qualify your
apology" to clarify that it's not the literal phrasing that's important,
but rather avoiding "#sorry #notsorry"