Support new websearch_tsquery() function

that was introduced in PostgreSQL 11

See https://www.postgresql.org/docs/11/static/textsearch-controls.html#TEXTSEARCH-PARSING-QUERIES
websearch_to_tsquery creates a tsquery value from querytext using an alternative syntax in which
simple unformatted text is a valid query. Unlike plainto_tsquery and phraseto_tsquery,
it also recognizes certain operators. Moreover, this function should never raise syntax errors,
which makes it possible to use raw user-supplied input for search.
The following syntax is supported:
 - unquoted text: text not inside quote marks will be converted to terms separated by & operators, as if processed by plainto_tsquery.
 - "quoted text": text inside quote marks will be converted to terms separated by <-> operators, as if processed by phraseto_tsquery.
 - OR: logical or will be converted to the | operator.
 - -: the logical not operator, converted to the the ! operator.

Author: pmatseykanets

src/PostgresEngineServiceProvider.php

@@ -8,13 +8,17 @@
 use ScoutEngines\Postgres\TsQuery\ToTsQuery;
 use ScoutEngines\Postgres\TsQuery\PlainToTsQuery;
 use ScoutEngines\Postgres\TsQuery\PhraseToTsQuery;
+use ScoutEngines\Postgres\TsQuery\WebSearchToTsQuery;
 
 class PostgresEngineServiceProvider extends ServiceProvider
 {
     public function boot()
     {
         $this->app->make(EngineManager::class)->extend('pgsql', function () {
-            return new PostgresEngine($this->app['db'], $this->app['config']->get('scout.pgsql', []));
+            return new PostgresEngine(
+                $this->app->get('db'),
+                $this->app->get('config')->get('scout.pgsql', [])
+            );
         });
 
         if (! Builder::hasMacro('usingPhraseQuery')) {
@@ -46,5 +50,15 @@ public function boot()
                 return $this;
             });
         }
+
+        if (! Builder::hasMacro('usingWebSearchQuery')) {
+            Builder::macro('usingWebSearchQuery', function () {
+                $this->callback = function ($builder, $config) {
+                    return new WebSearchToTsQuery($builder->query, $config);
+                };
+
+                return $this;
+            });
+        }
     }
 }

src/TsQuery/WebSearchToTsQuery.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace ScoutEngines\Postgres\TsQuery;
+
+class WebSearchToTsQuery extends BaseTsQueryable
+{
+    protected $tsFunction = 'websearch_tsquery';
+}