Use struct identifiers in comments before the value.
This has some advantages:
- The struct identifiers didn't mix well with other code-comments,
where other comments were wrapped onto the next line.
- Minor changes could re-align all other comments in the struct.
- PyVarObject_HEAD_INIT & tp_name are no longer placed on the same line.
Remove overly verbose comments copied from PyTypeObject (Python v2.x),
these aren't especially helpful and get outdated.
Also corrected some outdated names:
- PyTypeObject.tp_print -> tp_vectorcall_offset
- PyTypeObject.tp_reserved -> tp_as_async