Modify Parser/asdl_c.py so that the __version__ number for Python/Python-ast.c
is specified at the top of the file. Also add a note that Python/Python-ast.c
needs to be committed separately after a change to the AST grammar to capture
the revision number of the change (which is what __version__ is set to).
diff --git a/Include/Python-ast.h b/Include/Python-ast.h
index 5d4147b..8b395a8 100644
--- a/Include/Python-ast.h
+++ b/Include/Python-ast.h
@@ -1,4 +1,4 @@
-/* File automatically generated by Parser/asdl_c.py */
+/* File automatically generated by Parser/asdl_c.py. */
#include "asdl.h"