fix missing exercise-id in reset-exercise subcommand

Author: Heliozoa

tmc-langs-cli/src/app.rs

@@ -488,6 +488,11 @@ fn create_core_app() -> App<'static, 'static> {
                 .long("exercise-path")
                 .required(true)
                 .takes_value(true))
+            .arg(Arg::with_name("exercise-id")
+                .help("The ID of the exercise.")
+                .long("exercise-id")
+                .required(true)
+                .takes_value(true))
             .arg(Arg::with_name("save-old-state")
                 .help("If set, the exercise is submitted to the server before resetting it.")
                 .long("save-old-state")