chore: add missing file headers

interpreter/src/types.rs

@@ -1,3 +1,8 @@
+// This file is part of the uutils awk package.
+//
+// For the full copyright and license information, please view the LICENSE
+// files that was distributed with this source code.
+
 use std::{
     borrow::Cow,
     fmt::Display,

interpreter/src/vm.rs

@@ -1,3 +1,8 @@
+// This file is part of the uutils awk package.
+//
+// For the full copyright and license information, please view the LICENSE
+// files that was distributed with this source code.
+
 use std::{
     fmt::{self, Display},
     mem::replace,