[9.x] Adds types to makeAllSearchableUsing (#660)

* Adds types to `makeAllSearchableUsing`

* Apply fixes from StyleCI

---------

Co-authored-by: StyleCI Bot <[email protected]>

Author: nunomaduro

src/Searchable.php

@@ -2,6 +2,7 @@
 
 namespace Laravel\Scout;
 
+use Illuminate\Database\Eloquent\Builder as EloquentBuilder;
 use Illuminate\Database\Eloquent\SoftDeletes;
 use Illuminate\Support\Collection as BaseCollection;
 use Illuminate\Support\Str;
@@ -155,7 +156,7 @@ public static function makeAllSearchable($chunk = null)
      * @param  \Illuminate\Database\Eloquent\Builder  $query
      * @return \Illuminate\Database\Eloquent\Builder
      */
-    protected function makeAllSearchableUsing($query)
+    protected function makeAllSearchableUsing(EloquentBuilder $query)
     {
         return $query;
     }