bpo-42972: Fix sqlite3 traverse/clear functions (GH-26452) (GH-26461)

(cherry picked from commit d1124b09e8251061dc040cbd396f35ae57783f4a)

Co-authored-by: Erlend Egeberg Aasland <erlend.aasland@innova.no>
diff --git a/Modules/_sqlite/connection.h b/Modules/_sqlite/connection.h
index 82f6baf..8773c9e 100644
--- a/Modules/_sqlite/connection.h
+++ b/Modules/_sqlite/connection.h
@@ -93,7 +93,7 @@ typedef struct
     /* a dictionary of registered collation name => collation callable mappings */
     PyObject* collations;
 
-    /* Exception objects */
+    /* Exception objects: borrowed refs. */
     PyObject* Warning;
     PyObject* Error;
     PyObject* InterfaceError;