Document that resp.status overwrites resp.reason.

For those cases where you want to send a different reason
message, but use the normal status code.

Noticed by Kacper when doing 301/302 in vcl_synth().

lib/libvcc/generate.py

@@ -689,6 +689,9 @@ sp_variables = [
 		( 'deliver', 'synth', ),
 		( 'deliver', 'synth', ), """
 		The HTTP status code that will be returned.
+
+                Assigning a HTTP standardized code to resp.status will also
+                set resp.reason to the corresponding status message.
 		"""
 	),
 	('resp.reason',