Close the \ActionStdCancel correctly so that the following space won't be eaten.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27285 a1c6a512-1295-4272-9138-f99709370657
diff --git a/manual/advanced_topics/main.tex b/manual/advanced_topics/main.tex
index f0857aa..eb2b7b7 100644
--- a/manual/advanced_topics/main.tex
+++ b/manual/advanced_topics/main.tex
@@ -552,7 +552,7 @@
 \item [Browse .cfg Files]Opens the \setting{File Browser} in the
   \fname{/.rockbox} directory and displays all \fname{.cfg} (configuration)
   files. Selecting a \fname{.cfg} file will cause Rockbox to load the settings
-  contained in that file. Pressing \ActionStdCancel will exit back to the
+  contained in that file. Pressing \ActionStdCancel{} will exit back to the
   \setting{Manage Settings} menu. See the \setting{Write .cfg files} option on
   the \setting{Manage Settings} menu for details of how to save and edit a 
   configuration file.