update substitute-expression definition

larcs.org

@@ -105,7 +105,7 @@ Note that ~eqal~ will handle ~type-error~ by trying to switch the order of the a
   (defgeneric copy-expression (expression))
 
   @export
-  (defgeneric substitute-expression (expression with in))
+  (defgeneric substitute-expression (replace replacement expression))
 
   @export
   (defgeneric evaluate (expression &key substitutions-list resolve-constants-light-p resolve-constants-hard-p))