Still cleaning up/DRYing up/fixing smallish bugs in the decorators, but calling it a night.

- Previous `#_split_paragraph` mixin function (and spec) now utility class `ParagraphSplitter`, and much cleaner for the experience.
- Comment decorator still a massive snarl in #format_entire_comment. Should call #explode_spaghetti_factory while it's at it.
- Article decorator doesn't have anything that bad, but somehow some of my changes like #format_keywords and #format_links got rolled back.

All in all, obvious that 3.47 AM is way too late to push this puppy.