Represents a type path in the AST.
Sub is set on module sub-type access:
`pack.Module.Type` has `name = "Module"`, `sub = "Type"`, if available.
The position of the dot-path itself, without type parameters.
The full position of the type path, including type parameters.
Optional parameters of the type path.
Represents the package of the type path.
The name of the type path.