Add command suggestion when there are no stacklets

rust/stackablectl/src/cmds/stacklet.rs

@@ -99,7 +99,21 @@ async fn list_cmd(args: &StackletListArgs, cli: &Cli) -> Result<String, CmdError
         .context(StackletListSnafu)?;
 
     if stacklets.is_empty() {
-        return Ok("No stacklets".into());
+        let mut result = cli.result();
+
+        result
+            .with_command_hint(
+                "stackablectl stack install <STACK_NAME>",
+                "install a complete stack",
+            )
+            .with_command_hint(
+                "stackablectl demo install <DEMO_NAME>",
+                "install an end-to-end demo",
+            )
+            .with_output("No stacklets found");
+
+        // TODO (Techassi): Remove unwrap
+        return Ok(result.render().unwrap());
     }
 
     match args.output_type {

rust/stackablectl/src/output/mod.rs

@@ -57,9 +57,9 @@ where
             "{}",
             color_print::cformat!("An unrecoverable error occured: <s><r>{}</></>\n\n", self)
         )?;
-        write!(
+        writeln!(
             report,
-            "Caused by these errors (recent errors listed first):\n"
+            "Caused by these errors (recent errors listed first):"
         )?;
 
         let mut error: &dyn std::error::Error = &self;