This change ports the comments hint model and view to TypeScript, and

updates the UI to include the new commit range information. Along with

this, the implementation has been simplified a bit to attach event

handlers individually to each item in the list, rather than having a

generic event handler and setting data on the list items.

Ran js-tests.
Viewed a diff while having a review that had comments on lots of

  different revisions/interdiffs/commits. Saw that the comment hint

  correctly showed all of the revisions that had draft comments, and

  that clicking on all of them correctly loaded the associated revision.