Files demonstrate the old verse the new way of implmenting Solr Suggesters with Sitecore.

sample.solrconfig.xml

<!-- 
  Add this to the solrconfig.xml of all cores that need to support Suggest 
  See Solr documentation for full description of file: https://lucene.apache.org/solr/guide/6_6/suggester.html
-->

<searchComponent name="suggest" class="solr.SuggestComponent">
  <lst name="suggester">
    <str name="name">locationnamedict</str>
    <!-- Check Solr documentation for options for lookup and dictionary implementation -->
    <str name="lookupImpl">AnalyzingLookupFactory</str>
    <str name="dictionaryImpl">DocumentDictionaryFactory</str>
    <!-- Field in the index that auto suggest will be based on -->
    <str name="field">locationname_s</str>
    <!-- Additional details that you can leverage in rendering, normally used for grouping -->
    <str name="payloadField">locationbaselink_s</str>
    <!-- Be sure to mark as text_general to get case-insensitive results -->
    <str name="suggestAnalyzerFieldType">text_general</str>
    <str name="buildOnStartup">true</str>
  </lst>
  <lst name="suggester">
    <str name="name">servicenamedict</str>
    <str name="lookupImpl">AnalyzingLookupFactory</str>
    <str name="dictionaryImpl">DocumentDictionaryFactory</str>
    <str name="field">servicename_s</str>
    <str name="payloadField">service_s</str> 
    <str name="suggestAnalyzerFieldType">text_general</str>
    <str name="buildOnStartup">true</str>
  </lst>
</searchComponent>

<requestHandler name="/suggest" class="solr.SearchHandler" startup="lazy">
  <lst name="defaults">
    <str name="suggest.dictionary">locationnamedict</str>
    <str name="suggest.dictionary">servicenamedict</str>
    <str name="suggest">true</str>
    <str name="suggest.count">10</str>
  </lst>
  <arr name="components">
    <str>suggest</str>
  </arr>
</requestHandler>

SolrSuggestor-ApiSample.cs

/// <summary>
/// Solr Suggester Implementation via Sitecore API
/// </summary>
/// <param name="term"></param>
/// <returns></returns>
public IEnumerable<string> GetSuggestions(string term)
{
    if (term.Length < 3)
        return Enumerable.Empty<string>();

    using (var searchContext = ContentSearchManager.GetIndex("mysitecoreindex").CreateSearchContext())
    {
        SolrSuggestQuery q = term;
        var options = new SuggestHandlerQueryOptions
        {
            Parameters = new SuggestParameters { Count = 10, Build = true }
        };

        var result = searchContext.Suggest(q, options);
        List<string> suggestTerms = new List<string>();
        foreach(var suggestionDictionary in result.Suggestions)
        {
            foreach(var suggestTerm in suggestionDictionary.Value.Suggestions)
            {
                suggestTerms.Add(suggestTerm.Term);
            }

        }

        return locations;
    }

    return Enumerable.Empty<string>();
}

SolrSuggestor-ManualSample.cs

/// <summary>
/// Following is a sample of what a common manual implementation of managing the logic for Solr Suggest of a Sitecore search implementation
/// </summary>
/// <param name="term"></param>
/// <returns></returns>
public IEnumerable<string> GetAutoSuggest(string term)
{
    if (term.Length < 3)
      return Enumerable.Empty<string>();
      
    var queryString = new Dictionary<string, string>()
    {
        { "suggest", "true" },
        { "wt", "json" },
        { "suggest.build", "true" },
        { "suggest.q", term.Trim() }
    };

    List<string> suggestTerms = new List<string>();

    using (var httpClient = new HttpClient())
    {
        httpClient.BaseAddress = new Uri("https://solr662:8983/solr");//Really should be pulled from configuration
        var requestUri = QueryHelpers.AddQueryString("MyCustomSitecoreIndex/suggest", queryString);

        HttpResponseMessage response = await httpClient.PostAsync(requestUri).Result;
        var solrSuggestObj = JsonConvert.DeserializeObject<SolrSuggestModel>(response.Content.ToString());

        foreach (var suggestDictionary in solrSuggestObj.suggest)
        {
            foreach (var termSet in suggestDictionary.suggestions)
            {
                suggestTerms.Add(termSet.term);
            }
        }
    }

    return suggestTerms;
}