Add content for rule guidance containing "TO DO"s.

[danfiedler-msft]

Two primary changes here:

1. Removing [Ignore] from the test that verifies rule guidance does not contain "TODO" or "TO DO"
2. Adding content for all existing rule guidance that previously contained "TO DO" and making the markdown consistent.

This PR also removes the "Encryption Marked 'Optional'" rule (ID DS114352) as we could not determine what technology this rule was associated with (and therefore could write meaningful guidance.)