fix type => [value|element]_type

Fix style in tests

Forgot to add this file

Whitespace fix

Refactor LetBlock, allow single LetIn

0 == 0.0 so unfold line

Refactor UnionType#fetch

Switch to registry pattern for TypeChecker.for

Refactor TextLiteral typecheck

Refactor If typecheck

Refactor OperatorListConcatenate typecheck

Start refactor of list concat

Refactor OperatorRecursiveRecordMerge typechecker

Refactor OperatorRightBiasedRecordMerge typechecker

Refactor OperatorRecursiveRecordTypeMerge typecheck

Refactor List typecheck

Refactor Optional/None typecheck

Refactor AnonymousType typecheck

Refactor Record typecheck

Refactor RecordSelection typecheck