fix typo in org.texi

The attached patch fixes a typo in the documentation.
I hope I got the format of the commit message right.

Best regards,
   Jan

>From 7daa1f794794d515624ab28310db81a0e4099ea5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20B=C3=B6cker?= <jan.boecker@jboecker.de>
Date: Sat, 16 Jun 2012 15:04:43 +0200
Subject: [PATCH] org.texi: fix typo

* doc/org.texi (The spreadsheet): fix typo

doc/org.texi

@@ -2712,7 +2712,7 @@ modified in order to still reference the same field.  To avoid this from
 happening, in particular in range references, anchor ranges at the table
 borders (using @code{@@<}, @code{@@>}, @code{$<}, @code{$>}), or at hlines
 using the @code{@@I} notation.  Automatic adaptation of field references does
-of cause not happen if you edit the table structure with normal editing
+of course not happen if you edit the table structure with normal editing
 commands---then you must fix the equations yourself.
 
 Instead of typing an equation into the field, you may also use the following