* add deserialization test for MessageBodyRanges
* Add style ranges to MessageBodyText
* add deserialization tests and fix small other test
* add basic mention hydration tests
* Add RTL support for @mention hydration
* Add a test with accents for unicode shenanigans
* unique-ify TODOs
* Add emoji test and fix implementation to account for multi-point unicode that is captured in NSString.length but not String.count
* Add more TODOs for text formatting
* Collapse style ranges on init
* Handle mention overlaps on MessageBodyRanges init
* add tests, update existing tests, fix bugs
* Update v2 deserialization test; the meaning of Style raw values has changed
* comment nit
224e5a7c6b