Add syncback reminder for initialized projects

- Introduced a message prompting users to run 'rojo syncback' if a place ID is specified during project initialization, enhancing user guidance and workflow clarity.

src/cli/init.rs

@@ -200,6 +200,10 @@ impl InitCommand {
 
         println!("Created project successfully.");
 
+        if self.placeid.is_some() {
+            println!("Run 'rojo syncback' to sync your place.");
+        }
+
         Ok(())
     }
 }