This encompasses the "glue" code to get the data to a state for use in the article content and modal for highlighting. This is a large task (and not really testable by QA yet), and can be broken up into multiple PRs:

1. Fetch from endpoint created in https://phabricator.wikimedia.org/T270425 and deserialize the response.
2. We need to map the sentence selected in the mobile-html response (see https://phabricator.wikimedia.org/T270448 for sentence selection logic task) and find the corresponding sentence in the API response.
3. Turn that sentence into an array of objects that contain an NSAttributedString with proper highlighting corresponding to that editor's changes, plus revision and editor info. These will be used in the modal.