Cleaned up the docstring for readline.set_completer().
Thanks to Nathaniel Gray for reporting the confusion.
diff --git a/Modules/readline.c b/Modules/readline.c
index 29d8999..6469d27 100644
--- a/Modules/readline.c
+++ b/Modules/readline.c
@@ -266,7 +266,7 @@
set_completer([function]) -> None\n\
Set or remove the completer function.\n\
The function is called as function(text, state),\n\
-for i in [0, 1, 2, ...] until it returns a non-string.\n\
+for state in 0, 1, 2, ..., until it returns a non-string.\n\
It should return the next possible completion starting with 'text'.\
";