message: Add TODO comments to REPL
diff: @@ -59,6 +59,7 @@ pub fn run(options: Options) -> anyhow::Result<()> {
  print_welcome_banner()
  }
  + // TODO: Use appropriate directory on Windows
  let xdg_dirs = xdg::BaseDirectories::with_prefix("pikelet/repl")?;
  let history_path = xdg_dirs.get_data_home().join(HISTORY_FILE_NAME);
  @@ -90,6 +91,16 @@ pub fn run(options: Options) -> anyhow::Result<()> {
  }
  // TODO: Parse REPL commands
  + //
  + // Command Arguments Purpose
  + //
  + // <term> normalize a term in the context
  + // :? :h :help display this help text
  + // :core <term> print the core representation of a term
  + // :local <name> : <term> define a local assumption in the REPL context
  + // :local <name> = <term> define a local definition in the REPL context
  + // :q :quit quit the repl
  + // :t :type <term> infer the type of a term
  let surface_term = surface::Term::from_str(file.source(), &messages_tx);
  let (core_term, r#type) = state.synth_type(&surface_term);
  