`sys._clear_internal_caches()` no longer clears the type cache

### Documentation `Doc/library/sys.rst` says `sys._clear_type_cache()` clears the internal type cache, and that `sys._clear_internal_caches()` clears all internal performance-related caches. Neither does any more. Both reach it only through `PyType_ClearCache()`, which is now just `return NEXT_VERSION_TAG(interp) - 1;`. ```python import sys, _testinternalcapi class C: x = 'v' C.x # populate the per-type lookup cache print("cached: ", _testinternalcapi.type_cache_lookup(C, 'x')) sys._clear_type_cache() print("after sys._clear_type_cache: ", _testinternalcapi.type_cache_lookup(C, 'x')) sys._clear_internal_caches() print("after sys._clear_internal_caches:", _testinternalcapi.type_cache_lookup(C, 'x')) ``` ``` cached: (1, 'v', 131161) after sys._clear_type_cache: (1, 'v', 131161) after sys._clear_internal_caches: (1, 'v', 131161) ``` The C API side is already documented. `Doc/c-api/type.rst` says the function is now a no-op, and GH-150160 added a matching porting note. The Python wrappers look like the spot that was missed.