Update Objects/obmalloc.c

Co-authored-by: Victor Stinner <[email protected]>

Author: corona10

Objects/obmalloc.c

@@ -468,7 +468,7 @@ _PyMem_ArenaAlloc(void *Py_UNUSED(ctx), size_t size)
     if (ptr == MAP_FAILED)
         return NULL;
     assert(ptr != NULL);
-    _PyAnnotateMemoryMap(ptr, size, "cpython:obmalloc");
+    _PyAnnotateMemoryMap(ptr, size, "cpython:pymalloc");
     return ptr;
 #else
     return malloc(size);