Fix typo

Doc/howto/curses.tex

@@ -75,7 +75,7 @@ later.
 
 This HOWTO is simply an introduction to writing text-mode programs
 with curses and Python. It doesn't attempt to be a complete guide to
-the curses API; for that, see the Python library guide's serction on
+the curses API; for that, see the Python library guide's section on
 ncurses, and the C manual pages for ncurses.  It will, however, give
 you the basic ideas.