help I changed one currency in woocommerce and everything is ruined [closed]

Rather than attempting to modify a core file of woocommerce, make use of their filter hook. First of all, make sure you are using an up to date version of woocommerce.

From the woocommerce documentation Add a custom currency / symbol:

To add a custom currency in WooCommerce 2.0+, copy and paste this code
in your theme functions.php file and swap out the currency code and
symbol with your own.

After saving changes, it should be available from your WooCommerce
settings.

add_filter( 'woocommerce_currencies', 'add_my_currency' );

function add_my_currency( $currencies ) {
     $currencies['ABC'] = __( 'Currency name', 'woocommerce' );
     return $currencies;
}

add_filter('woocommerce_currency_symbol', 'add_my_currency_symbol', 10, 2);

function add_my_currency_symbol( $currency_symbol, $currency ) {
     switch( $currency ) {
          // Notice you are able to type the actual character instead of the hex value.
          case 'ABC': $currency_symbol="$"; break;
     }
     return $currency_symbol;
}

That said, your code probably failed because you did not use the hex value of the currency symbol you are replacing it with. I believe it would be 'MAD' => 'د...إ.', according to this reference on currency unicode values. There should not be a ) at the end either. See line 545 of wc-core-functions.php
.