now displaying missing binary instead of allways asciidoctro. Tested

src/app/build/asciidoctor.rs

@@ -12,9 +12,13 @@ fn exec_command(command: &mut process::Command) -> Result<(), String> {
         }
     } else {
         println!("{}", result.unwrap_err());
-        return Err(
+
-            "asciidoctor not installed. For more information run docki health!".to_string(),
+        let binary_name = command.get_program().to_str().unwrap_or("Something is");
-        );
+
+        return Err(format!(
+            "{} not installed. For more information run docki health!",
+            binary_name
+        ));
     }
 }