a typo fix for manual

[Wang Diancheng <dcwang redflag-linux com>]

diff --git a/man/sawfish.texi b/man/sawfish.texi
index b9c1b70..81d5153 100644
--- a/man/sawfish.texi
+++ b/man/sawfish.texi
@@ -753,7 +753,7 @@ Return a window object with class @var{class}, or @code{nil}.
 @end defun
 
 @defun get-window-by-class-re class
-Return a window object with class matchting regular expression
+Return a window object with class matching regular expression
 @var{class}, or @code{nil}.
 @end defun