convert shebang lines: python -> python3
diff --git a/Lib/symbol.py b/Lib/symbol.py
index ea8f2f5..e3fff34 100755
--- a/Lib/symbol.py
+++ b/Lib/symbol.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 
 """Non-terminal symbols of Python grammar (from "graminit.h")."""