fix attributes on public structs & enums

vlib/compiler/tests/attribute_test.v

@@ -0,0 +1,33 @@
+[testing]
+struct StructAttrTest {
+	foo string
+	bar int
+}
+
+[testing]
+pub struct PubStructAttrTest {
+	foo string
+	bar int
+}
+
+[testing]
+enum EnumAttrTest {
+	one
+	two
+}
+
+[testing]
+pub enum PubEnumAttrTest {
+	one
+	two
+}
+
+[testing]
+fn test_fn_attribte() {
+	assert true
+}
+
+[testing]
+pub fn test_pub_fn_attribte() {
+	assert true
+}