bpo-39322: Add gc.is_finalized to check if an object has been finalised by the gc (GH-17989)

diff --git a/Modules/clinic/gcmodule.c.h b/Modules/clinic/gcmodule.c.h
index 22d2aa4..72795c6 100644
--- a/Modules/clinic/gcmodule.c.h
+++ b/Modules/clinic/gcmodule.c.h
@@ -304,6 +304,15 @@
 #define GC_IS_TRACKED_METHODDEF    \
     {"is_tracked", (PyCFunction)gc_is_tracked, METH_O, gc_is_tracked__doc__},
 
+PyDoc_STRVAR(gc_is_finalized__doc__,
+"is_finalized($module, obj, /)\n"
+"--\n"
+"\n"
+"Returns true if the object has been already finalized by the GC.");
+
+#define GC_IS_FINALIZED_METHODDEF    \
+    {"is_finalized", (PyCFunction)gc_is_finalized, METH_O, gc_is_finalized__doc__},
+
 PyDoc_STRVAR(gc_freeze__doc__,
 "freeze($module, /)\n"
 "--\n"
@@ -373,4 +382,4 @@
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=e40d384b1f0d513c input=a9049054013a1b77]*/
+/*[clinic end generated code: output=bd6a8056989e2e69 input=a9049054013a1b77]*/