An error rendered through its checked-dynamic node (a runtime error class,
or an error held as a subclass's `cause`) prints a non-enumerable `cause`
as `[cause]: value` and an AggregateError's `errors` as `[errors]: [...]`,
after its enumerable properties, as Node's formatError does. Before, a
subclass's cause that was an Error constructed with a `cause` option
printed without it: `{ cause: [Error: inner] }` where Node prints
`{ cause: [Error: inner] { [cause]: 'deep' } }`.
Chris Tate
c90b321a5b