Document that PyInterpreterState_GetDict returns a borrowed reference (GH-139451)

(cherry picked from commit 80cdf3e)

Co-authored-by: Petr Viktorin <encukou@gmail.com>

Author: encukou

Doc/c-api/init.rst

@@ -1477,6 +1477,9 @@ All of the following functions must be called after :c:func:`Py_Initialize`.
    This is not a replacement for :c:func:`PyModule_GetState()`, which
    extensions should use to store interpreter-specific state information.
 
+   The returned dictionary is borrowed from the interpreter and is valid until
+   interpreter shutdown.
+
    .. versionadded:: 3.8
 
 

Doc/data/refcounts.dat

@@ -1148,6 +1148,9 @@ PyInterpreterState_Clear:PyInterpreterState*:interp::
 PyInterpreterState_Delete:void:::
 PyInterpreterState_Delete:PyInterpreterState*:interp::
 
+PyInterpreterState_GetDict:PyObject*::0:
+PyInterpreterState_GetDict:PyInterpreterState*:interp::
+
 PyInterpreterState_GetID:int64_t:::
 PyInterpreterState_GetID:PyInterpreterState*:interp::