Update Currency.php

Declare module namespace before template path

Author: mageprince

app/code/Magento/CurrencySymbol/Block/Adminhtml/System/Currency.php

@@ -16,7 +16,7 @@ class Currency extends \Magento\Backend\Block\Template
     /**
      * @var string
      */
-    protected $_template = 'system/currency/rates.phtml';
+    protected $_template = 'Magento_CurrencySymbol::system/currency/rates.phtml';
 
     /**
      * Prepare layout