atom: fix type of Task.send()'s message parameter (#22907)

* atom: fix type of Task.send()'s message parameter

* atom: disallow undefined message argument to Task.send()

* atom: remove unnecessary linter comment

* atom: allow nested arrays to be passed to Task.send()

types/atom/index.d.ts

@@ -4810,7 +4810,8 @@ export class Task {
      *  Throws an error if this task has already been terminated or if sending a
      *  message to the child process fails.
      */
-    send(message: string): void;
+    // tslint:disable-next-line:no-any
+    send(message: string | number | boolean | object | null | any[]): void;
 
     /** Call a function when an event is emitted by the child process. */
     // tslint:disable-next-line:no-any