- Special precedence rules for case-of so that `:` operator works without parens or nospace-grouping.
- Support an old-lambda syntax: `x->x-> x`. According to the usual rules, the first nospace group would be parsed as an operator section. The expression now parses as a lambda that contains a lambda.
- Match old parser treatment of # in doc comments.
- Tweak precedence so (a : B = c) works.
- Documented constructors.
- Implement macro-contexts-lite (`from` is now only a keyword at the beginning of a line)
- Support special nospace-group handling for old lambdas (so expressions like this work: `x-> y-> x + y`)
- Fix a text-escape incompatibility
# Important Notes
- There is now an `OperatorFunction`, which is like a `Function` but has an operator for a name, and likewise an `OperatorTypeSignature`.
