fix(types): Change Bun.serve types to allow void when using websockets (#7160)

* `Response` -> `any`

* Revert previous commit & allow void in ws fetch

* Added type test to check if you can upgrade connection without returning

* [autofix.ci] apply automated fixes

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

packages/bun-types/bun.d.ts

@@ -2014,7 +2014,7 @@ declare module "bun" {
       this: Server,
       request: Request,
       server: Server,
-    ): Response | undefined | Promise<Response | undefined>;
+    ): Response | undefined | void | Promise<Response | undefined | void>;
   }
 
   export interface UnixWebSocketServeOptions<WebSocketDataType = undefined>
@@ -2075,7 +2075,7 @@ declare module "bun" {
       this: Server,
       request: Request,
       server: Server,
-    ): Response | undefined | Promise<Response | undefined>;
+    ): Response | undefined | void | Promise<Response | undefined | void>;
   }
 
   export interface TLSWebSocketServeOptions<WebSocketDataType = undefined>

packages/bun-types/tests/serve.test-d.ts

@@ -79,6 +79,25 @@ Bun.serve<User>({
   },
 });
 
+Bun.serve({
+  fetch(req, server) {
+    server.upgrade(req);
+  },
+
+  websocket: {
+    open(ws) {
+      console.log("WebSocket opened");
+      ws.subscribe("test-channel");
+    },
+
+    message(ws, message) {
+      ws.publish("test-channel", `${message}`);
+    },
+
+    perMessageDeflate: true,
+  },
+});
+
 Bun.serve({
   fetch(req) {
     throw new Error("woops!");