Update LengthAwarePaginator.php (#15870)

Ran into minor problem using multiple LengthAwarePaginators on a single page with alternate 'pageName' properties. Traced problem to the attached proposed change.

When checking the current page for a LengthAwarePaginator instance, any non-default pageName is not sent to resolveCurrentPage and as such 1 is always returned (unless pageName of 'page' is used).

src/Illuminate/Pagination/LengthAwarePaginator.php

@@ -48,20 +48,20 @@ public function __construct($items, $total, $perPage, $currentPage = null, array
         $this->perPage = $perPage;
         $this->lastPage = (int) ceil($total / $perPage);
         $this->path = $this->path != '/' ? rtrim($this->path, '/') : $this->path;
-        $this->currentPage = $this->setCurrentPage($currentPage, $this->lastPage);
+        $this->currentPage = $this->setCurrentPage($currentPage, $this->pageName);
         $this->items = $items instanceof Collection ? $items : Collection::make($items);
     }
 
     /**
      * Get the current page for the request.
      *
      * @param  int  $currentPage
-     * @param  int  $lastPage
+     * @param  string  $pageName
      * @return int
      */
-    protected function setCurrentPage($currentPage, $lastPage)
+    protected function setCurrentPage($currentPage, $pageName)
     {
-        $currentPage = $currentPage ?: static::resolveCurrentPage();
+        $currentPage = $currentPage ?: static::resolveCurrentPage($pageName);
 
         return $this->isValidPageNumber($currentPage) ? (int) $currentPage : 1;
     }