R1:74644d521027

move ponder writes into editors; better search indexing

Summary:
* Moved the remaining `->save()` calls into editors
* for the `PonderQuestion`, separate `attachRelated` (needed for
indexing and viewing) from `attachVotes` (needed for viewing
but not indexing)
* Update the indexer to include comment and answer content
in the search index.

Test Plan:
Stuff works as before. Also: add a comment or answer with some
easily-identifiable text and search for it; observe that
it gets indexed appropriately.