fix: invalid ipv6 hostname on `deno serve` (#25482)

This PR fixes an invalid URL being printed when running `deno serve`

Before: invalid URL

```sh
$ deno serve --host localhost
deno serve: Listening on http://::1:8000/
```

After: valid URL

```sh
$ deno serve --host localhost
deno serve: Listening on http://[::1]:8000/
```

1 files changed, 30 insertions, 0 deletions

diff --git a/tests/unit/serve_test.ts b/tests/unit/serve_test.ts
index 19a8ccad1..9d23f8df2 100644
--- a/tests/unit/serve_test.ts
+++ b/tests/unit/serve_test.ts
@@ -872,6 +872,36 @@ Deno.test({ permissions: { net: true } }, async function validPortString() {
   await server.shutdown();
 });
 
+Deno.test({ permissions: { net: true } }, async function ipv6Hostname() {
+  const ac = new AbortController();
+  let url = "";
+
+  const consoleLog = console.log;
+  console.log = (msg) => {
+    try {
+      const match = msg.match(/Listening on (http:\/\/(.*?):(\d+)\/)/);
+      assert(!!match, `Didn't match ${msg}`);
+      url = match[1];
+    } finally {
+      ac.abort();
+    }
+  };
+
+  try {
+    const server = Deno.serve({
+      handler: () => new Response(),
+      hostname: "::1",
+      port: 0,
+      signal: ac.signal,
+    });
+    assertEquals(server.addr.transport, "tcp");
+    assert(new URL(url), `Not a valid URL "${url}"`);
+    await server.shutdown();
+  } finally {
+    console.log = consoleLog;
+  }
+});
+
 Deno.test({ permissions: { net: true } }, function invalidPortFloat() {
   assertThrows(
     () =>