(FACT-705) Improve documentation of structured facts

Prior to this commit, the Facter core documentation did not
specify which facts were structured. In addition, the documentation
for several structured facts did not adequately describe the contents
of the fact.

This commit improves the header comments for several structured facts,
which are used to auto-generate the Facter core docs. Formatting was
used in accordance with the tool used to generate our core docs, which
can be found here: https://github.com/holguinj/extracter.
Merge pull request #809 from whopper/fact-705/document-structured-facts

(FACT-705) Improve documentation of structured facts
(maint) fix filename for acceptance sshkey

The boostrap script `acceptance/bin/ci-bootstrap-from-artifacts.sh` uses
an outdated filename/SSH key for our acceptance runs. We've been
(temporarily) hacking around this by sed'ing this file in our Jenkins
jobs. This commit fixes the filename in the script itself.
Merge pull request #810 from rji/maint/stable/acceptance-sshkey

(maint) fix filename for acceptance sshkey
Merge branch 'stable'