please select a value that is no more than

It should be possible to alter the browser’s default messages if you can write some javascript. This post explains the method:
http://www.sagarganatra.com/2011/07/custom-validation-messages-for-html5.html

Next you will also need to load your javascript into the page with something like:

<?php
add_action( 'wp_enqueue_scripts', 'add_my_script' );
function add_my_script() {
  wp_enqueue_script( 'my-js', '/wp-content/uploads/my_script.js', array(), "1", true);
}

Another approach to try would be to copy
wp-content/plugins/woocommerce/templates/global/quantity-input.php
to
wp-content/themes/your-theme/woocommerce/global/quantity-input.php
and in the copy, change the input type from number to text. There may be consequences which will need to be debugged. PHP skills would be required.