Small change in design.

design_muesli.muesli

@@ -90,7 +90,7 @@ command {
     print "second block"
 }
 
-# In Muesli al values are typed. Types can be defined by the built type command.
+# In Muesli all values are typed. Types can be defined by the built type command.
 type Door ( object locked Bool keys Item[] )
 
 # Commands can be defined by the built in 'to' command.