[MAYBE MERGE/MERGE THIRD] Use smartdown version with markdown public API

Update smartdown version with the changes to the api - returning markdown instead of html.

We may want to hold off merging this and bump to 0.11.2 instead as that version has a couple of bug fixes (although I do not think they are manifested anywhere in smart-answers), we would need to create a separate version bump commit anyway)
*nitpick o' clock*: maybe since we're always doing `Govspeak::Document.new(the_thing).to_html.html_safe` in three cases a helper method?