fix readable#read type

node/node.d.ts

@@ -1210,7 +1210,7 @@ declare module "stream" {
         readable: boolean;
         constructor(opts?: ReadableOptions);
         _read(size: number): void;
-        read(size?: number): any;
+        read(size?: number): string|Buffer;
         setEncoding(encoding: string): void;
         pause(): void;
         resume(): void;