Allow autocomplete suggestions to be altered

The current results displayed in the autocomplete suggestions are based on which terms would return the most results. A site may want to prioritize certain suggestions even if they have fewer (but more important) results.

A custom module would be able to alter the suggestions if this module added a drupal_alter() in apachesolr_autocomplete_callback() before drupal_json_output($result).

For example:

// Invoke any modules that want to alter the results to show.
// function MODULENAME_apachesolr_autocomplete_results_alter(&$results) { }
drupal_alter('apachesolr_autocomplete_results', $results);