Fix punctuation glitches in file-tree-walk docstring.

* files.el (file-tree-walk): Fix docstring.

lisp/ChangeLog

+2014-12-03  Eric S. Raymond  <esr@snark.thyrsus.com>
+
+	* files.el (file-tree-walk): Fix docstring.
+
 2014-12-03  Karl Fogel  <kfogel@red-bean.com>
 
 	Fix bug whereby saving files hung in VC hook.

lisp/files.el

@@ -730,11 +730,11 @@ The path separator is colon in GNU and GNU-like systems."
        (error "No such directory found via CDPATH environment variable"))))
 
 (defun file-tree-walk (dir action &rest args)
-  "Walk DIR executing ACTION.  Each call gets as arguments DIR, a file path,
-and optional ARGS. The ACTION is applied to each subdirectory
-before descending into it, and if nil is returned at that point
-the descent will be prevented.  Directory entries are sorted with
-string-lessp"
+  "Walk DIR executing ACTION on each path, with ARGS as additional arguments.
+Each call gets as arguments DIR, a file path, and optional ARGS.
+The ACTION is applied to each subdirectory before descending into
+it, and if nil is returned at that point the descent will be
+prevented.  Directory entries are sorted with string-lessp."
   (cond ((file-directory-p dir)
 	 (or (char-equal ?/ (aref dir (1- (length dir))))
 	     (setq dir (file-name-as-directory dir)))