Method substitute

src/main/java/wyil/lang/WyilFile.java:6240–6251

(java.util.function.Function<Object, Syntactic.Item> binding)

			}

			@Override
			public Type substitute(java.util.function.Function<Object, Syntactic.Item> binding) {
				Type[] before = getAll();
				Type[] after = WyilFile.substitute(before, binding);
				if(after == null) {
					return null;
				} else if (before == after) {
					return this;
				} else {
					return create(after);
				}
			}

			@Override
			public Type.Union clone(Syntactic.Item[] operands) {