bpo-41215: Don't use NULL by default in the PEG parser keyword list (GH-21355)



Automerge-Triggered-By: @lysnikolaou
diff --git a/Parser/parser.c b/Parser/parser.c
index bfd5c47..75dc717 100644
--- a/Parser/parser.c
+++ b/Parser/parser.c
@@ -9,8 +9,8 @@
 #endif
 static const int n_keyword_lists = 9;
 static KeywordToken *reserved_keywords[] = {
-    NULL,
-    NULL,
+    (KeywordToken[]) {{NULL, -1}},
+    (KeywordToken[]) {{NULL, -1}},
     (KeywordToken[]) {
         {"if", 510},
         {"in", 518},