Revise `pycore_stackref.h` comments. (#130601)

diff --git a/Include/internal/pycore_stackref.h b/Include/internal/pycore_stackref.h
index 80e8f4f365f1da5cfd2512567671716857bf10c2..e2e32ed4122838be9915a8771d86f5e7f413b993 100644 (file)
--- a/Include/internal/pycore_stackref.h
+++ b/Include/internal/pycore_stackref.h
@@ -35,13 +35,13 @@ extern "C" {
   unboxed integers harder in the future.
 
   Steal means that ownership is transferred to something else. The total
-  number of references to the object stays the same.
+  number of references to the object stays the same.  The old reference is no
+  longer valid.
 
   New creates a new reference from the old reference. The old reference
   is still valid.
 
-  With these 3 API, a strict stack discipline must be maintained. All
-  _PyStackRef must be operated on by the new reference operations:
+  All _PyStackRef must be operated on by the new reference operations:
 
     1. DUP
     2. CLOSE