Use `intern' not `intern-soft'
Return to use 1 not defun for forXXX forms.

This is no worse than DrRacket.

Eventually should write a custom indent function similar to
racket--indent-for/fold, but which can handle an _optional_ `: type`
annotation preceding the clauses.
Fix comment typo.
Change font-lock for definitions.

Fix issue with single-argument function definition.

Handle more definition things, e.g. define-types.
Add λ and require/typed keywords