- Generalize the syntax for the type of a stack effect to allow a trailing `*`,
so we can declare something as e.g. `PyCodeObject *`.
- When generating assignments for stack effects,
the type of the value on the stack should be the default (i.e., `PyObject *`)
even when the variable copied to/from it has a different type,
so that an appropriate cast is generated
However, not when the variable is an array --
then the type is taken from the variable (as it is always `PyObject **`).