Get the collation query from the spellcheck suggestions

Problem/Motivation

I needed a way to get the collation query when solr spellcheck is active and collation is enabled.

Proposed resolution

I added code to the SearchApiSpellcheckSolr class that gets the collation if available and saves it into the collation public field. There are no workarounds.

Remaining tasks

Reviews needed, documentation needed.

User interface changes

None

API changes

Here is how I used this:

  if (!empty($results['search_api_spellcheck'])) {
    $solr_sp = $results['search_api_spellcheck'];
    $collation = "";
    if (!empty($solr_sp->collation))
      $collation = $solr_sp->collation;