fix: show searchPanes by default when initialized

fixes the ff:
- yajra/laravel-datatables#2475 (comment)
- yajra/laravel-datatables-docs#74 (comment)

Author: yajra

src/Html/SearchPane.php

@@ -10,6 +10,11 @@
 
 class SearchPane extends Fluent
 {
+    public function __construct($attributes = [])
+    {
+        parent::__construct(['show' => true] + $attributes);
+    }
+
     /**
      * @param  array  $options
      * @return static