Convert annotations to attributes in Tamper plugins (requires 10.2+)

I do indeed get no Tamper plugin to choose from (using Feeds Tamper):

I think that TamperManager needs a change.

For example, \Drupal\filter\FilterPluginManager in Drupal 11.x has a reference to the attribute class:

use Drupal\filter\Attribute\Filter;

I've updated the conversion:

• category is made translatable.
• new property itemUsage is now converted too.
• plugins that were added this year ('absolute_url', 'entity_finder' and 'twig') have now also conversions.

I exported the definitions from before this change and after this change and then compared the two files to see if I spotted any differences that would be an error and did not see errors. There were slight differences in the plugin's descriptions. For some plugins, single quotes in the description were replaced with double quotes. But that's no error.

I used the following code for exporting the definitions:

drupal_flush_all_caches();

$keys = [
  'id',
  'label',
  'description',
  'category',
  'handle_multiples',
  'itemUsage',
];

$rows = [];
foreach (\Drupal::service('plugin.manager.tamper')->getDefinitions() as $definition) {
  $row = [];
  foreach ($keys as $key) {
    if (!array_key_exists($key, $definition)) {
      $row[$key] = 'undefined';
    }
    elseif (is_object($definition[$key])) {
      $row[$key] = (string) $definition[$key] .  ' (' . get_class($definition[$key]) . ')';
    }
    else {
      ob_start();
      var_dump($definition[$key]);
      $row[$key] = ob_get_clean();
      $row[$key] = trim($row[$key]);
    }
  }
  $rows[$definition['id']] = $row;
}
ksort($rows);

file_put_contents('/tmp/defs2.txt', print_r($rows, TRUE));

This is good, so I've scheduled to merge the changes.