Finish removing all implicit anys

src/addons/attach/attach.ts

@@ -36,7 +36,8 @@ export function attach(term: Terminal, socket: WebSocket, bidirectional: boolean
     }
   };
 
-  let myTextDecoder: TextDecoder;
+  // TODO: This should be typed but there seem to be issues importing the type
+  let myTextDecoder: any;
 
   addonTerminal.__getMessage = function(ev: MessageEvent): void {
     let str: string;