tp_dealloc example may need the trashcan for GC container types #158619

Documentation

The tp_dealloc Complete Example has no trashcan, and calls PyObject_CallFinalizerFromDealloc() before anything else. A GC type whose instances can reference other instances of the same type recurses without bound if it follows that shape.

Since the macros Py_TRASHCAN_BEGIN / Py_TRASHCAN_END are not in the C API reference at all, that example is the natural thing to copy for a new GC type. Would a note there make sense, or is the trashcan deliberately out of scope for the ref docs? It is also not clear to me whether gh-124715 and gh-132280 already solve this from 3.14 on.