title: Override External Product URL to "Add to Cart" product button
body: <p>I work on site that use External products from Amazon, but want instead pointing users to that external URL, first to add to cart that product. I have this function, that change Default Button text for each product, to Add to cart.</p>
  
  <pre><code>function sv_wc_external_product_button( $button_text, $product ) {
  
      if ( 'external' === $product-&gt;get_type() ) {
          // enter the default text for external products
          return $product-&gt;button_text ? $product-&gt;button_text : 'Add To Cart';
      }
      return $button_text;
  }
  add_filter( 'woocommerce_product_single_add_to_cart_text', 
  'sv_wc_external_product_button', 10, 2 );
  </code></pre>
  
  <p>But this function not add product to cart. </p>
  
  <p>How to make this function to Add selected product to cart? </p>
  
  <p>Thanks.</p>