It was in order to normalize the type output.  `{'a': 2}` would type as `{'a': Number}` whereas `{"a": 2}` would type as `{"a": Number}`.  Seemed a bit inconsistent to me as either version is a valid string and the repl would print the object as `{"a": 2}` in either case.  Also, it apparently didn't type nested quotes properly, so I've fixed that.