This makes things a little clearer when these nodes are not of type Parameter,
but actually Expr.

We don't yet parse or construct nodes of this type.

No support yet for calling them.

Simplest way to support things like "Boolean" seemed to be to make boolean a
keyword.

No code generation support yet.

It seems Flex needs to be told manually to adjust for the length of an operator.
This fixes some minor issues with enum and array definitions in the AST dump
output.

These are still not quite accurate.

This is still off by the length of the ID, but previously it was taking the
location of the entire accrued list, which was clearly wrong.

This reveals some problematic issues with the location of ID tokens. E.g. in the
context of an enum, its members do not get correct location information.

This will help when we switch to a srcML-like output.

For use in upcoming AST dumper related changes.

Useful for debugging and some other exploratory work.

Github: related to #47 "properties, covers, etc"

See the checker comment for an explanation of the motivation.

Github: related to #47 "properties, covers, etc"

Github: related to #47 "properties, covers, etc"

This is currently stubbed out.

Github: related to #47 "properties, covers, etc"

Github: fixes #54 "option to report multiple errors"