name comment

src/lib/Enumerable.vala

@@ -338,6 +338,11 @@ namespace Invercargill {
         }
 
         // Can't name it union because of C reserved keywords
+        // New names
+        // - union: combine or merge
+        // - intersect: overlap or common
+        // - difference: exclude or subtract
+        // - symmetric difference: mismatch or disjoint
         public virtual Enumerable<T> union(Enumerable<T> other, owned HashDelegate<T>? hash_func = null, owned EqualityDelegate<T>? equal_func = null) {
             return union_by<T>(other, i => i, (owned)hash_func, (owned) equal_func);
         }