[SyntaxParse] Parse generic parameter clause and generic where clause

utils/gyb_syntax_support/NodeSerializationCodes.py

@@ -233,6 +233,9 @@ SYNTAX_NODE_SERIALIZATION_CODES = {
     'PoundAssertStmt': 229,
     'SomeType': 230,
     'CustomAttribute': 231,
+    'GenericRequirement': 232,
+    'LayoutRequirement': 233,
+    'LayoutConstraint': 234,
 }