Try to improve grammar further.

Doc/howto/doanddont.tex

@@ -288,7 +288,7 @@ More useful functions in \module{os.path}: \function{basename},
 There are also many useful builtin functions people seem not to be
 aware of for some reason: \function{min()} and \function{max()} can
 find the minimum/maximum of any sequence with comparable semantics,
-for example, yet many people write they own
+for example, yet many people write their own
 \function{max()}/\function{min()}. Another highly useful function is
 \function{reduce()}. A classical use of \function{reduce()}
 is something like