Fix a typo in description

Thanks to Joachim Backes.

https://bugzilla.redhat.com/show_bug.cgi?id=960408

file-roller.spec

@@ -39,7 +39,7 @@ Requires: %{name} = %{version}-%{release}
 
 %description nautilus
 This package contains the file-roller extension for the nautilus file manger.
-It adds an item to the nautilus contexst menu that lets you compress files
+It adds an item to the nautilus context menu that lets you compress files
 or directories.
 
 %prep