chore(cli): improve "waiting for dev server" message, closes #3491 (#3504)

.changes/cli-improve-waiting-devserver-msg.md

@@ -0,0 +1,6 @@
+---
+"cli.rs": patch
+"cli.js": patch
+---
+
+Improve "waiting for your dev server to start" message.

tooling/cli/src/dev.rs

@@ -210,7 +210,10 @@ pub fn command(options: Options) -> Result<()> {
           break;
         }
         if i % 3 == 0 {
-          logger.warn("Waiting for your dev server to start...");
+          logger.warn(format!(
+            "Waiting for your frontend dev server to start on {}...",
+            dev_server_url
+          ));
         }
         i += 1;
         if i == max_attempts {