fix typo

TODO

diff --git a/TODO b/TODO
index ee5067b..2019708 100644
--- a/TODO
+++ b/TODO
@@ -168,7 +168,7 @@
         delete the temporary file.)
 
 ZIP_SOURCE_SEEK
-        Set postion for next read or write, a la fseek(3).
+        Set position for next read or write, a la fseek(3).
 
 ZIP_SOURCE_SUPPORTS
         Query which commands are supported for this stream.  If a