cli: allow string template argument in cli

closes #228

alib2cli/src/parser/Parser.cpp

@@ -121,7 +121,10 @@ std::unique_ptr < Arg > Parser::optional_arg ( ) {
 std::unique_ptr < Arg > Parser::template_arg ( ) {
 	match ( cli::Lexer::TokenType::AT_SIGN );
-	return arg ( );
+	if ( check ( cli::Lexer::TokenType::STRING ) )
+		return std::make_unique < ImmediateArg > ( matchString ( ) );
+	else
+		return arg ( );
 }
 std::unique_ptr < Arg > Parser::optional_variable ( ) {