* chore: Make sure copyright header comment includes license
* Add period at end of copyright line in checkCopyrightHeaders.js :)
* Update CHANGELOG.md
* expect: Improve report when matcher fails, part 20
* Added newlines to cleanupSemantic
* Add Facebook copyright header to declarations
* Added exception to checkCopyrightHeaders script
* Update CHANGELOG.md
* Make substring highlight explicit in CHANGELOG.md
* Convert cleanupSemantic to TypeScript
* Add diff-sequences to references in tsconfig.json
* Delete unneeded toString method of Diff class
* Add condition for edge case of empty string
* Decide not to rename DIFF_EQUAL
* Rewrite complicated condition as its plain meaning
* Encapsulate substring diff in array subclass with toJSON method
* Move printDiffOrStringify to jest-matcher-utils
* Add copyright header to 2 added files