markup adjustments
diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index e0a43eb..760d13a 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -1050,10 +1050,9 @@
Availability: Macintosh, \UNIX, Windows.
\end{funcdesc}
-\begin{funcdesc}{walk}{top\optional{, topdown=True}}
+\begin{funcdesc}{walk}{top\optional{, topdown\code{=True}}}
\index{directory!walking}
\index{directory!traversal}
-
\function{walk()} generates the file names in a directory tree.
For each directory in the tree rooted at directory \var{top} (including
\var{top} itself), it yields a 3-tuple
@@ -1064,7 +1063,7 @@
(excluding \code{'.'} and \code{'..'}). \var{filenames} is a list of
the names of the non-directory files in \var{dirpath}. Note that the
names in the lists contain no path components. To get a full
-path (which begins with \var{top)) to a file or directory in
+path (which begins with \var{top}) to a file or directory in
\var{dirpath}, do \code{os.path.join(\var{dirpath}, \var{name})}.
If optional argument \var{topdown} is true or not specified, the triple
@@ -1085,7 +1084,7 @@
\begin{notice}
If you pass a relative pathname, don't change the current working
-directory between resumptions of \function{walk}. \function{walk}
+directory between resumptions of \function{walk()}. \function{walk()}
never changes the current directory, and assumes that its caller
doesn't either.
\end{notice}
@@ -1095,7 +1094,7 @@
in \var{dirnames} lists, but \function{walk()} will not visit them
(infinite loops are hard to avoid when following symbolic links).
To visit linked directories, you can identify them with
-\code{os.path.islink(\var{path})}, and invoke \function{walk(\var{path})}
+\code{os.path.islink(\var{path})}, and invoke \code{walk(\var{path})}
on each directly.
\end{notice}