ret_expr -> return_expr

This matches Python's AST a little more closely

test/simple_source/looping/07_return_end_if.py

@@ -1,22 +1,22 @@
 # 2.6.9 asynchat.py
 # 2.6 added:
-# return_stmt ::= ret_expr RETURN_END_IF come_from_pop
-def initiate_send(self):
+# return_stmt ::= return_expr RETURN_END_IF come_from_pop
+def initiate_send(self, x):
     while self:
         if self:
             x = 'a'
         else:
             del self.producer_fifo[0]
-        return
+        return x
 
 # 2.6.9 contextlib.py
 # Bug was in return exc, so added:
-# return_stmt ::= ret_expr RETURN_VALUE_IF come_from_pop
+# return_stmt ::= return_expr RETURN_VALUE_IF come_from_pop
 
 def __exit__(self, type, value, traceback):
     try:
         raise RuntimeError
     except StopIteration:
-        return exc
+        return value
     except:
         raise