Missing line break in NIU Mini readme (#1886)

* Missing line break

* More specific URL to the product

keyboards/niu_mini/readme.md

@@ -5,9 +5,9 @@ NIU Mini
 
 A compact 40% (12x4) ortholinear keyboard kit sold by KBDFans.
 
-Keyboard Maintainer: QMK Community
+Keyboard Maintainer: QMK Community  
 Hardware Supported: NIU Mini PCB  
-Hardware Availability: [KBDFans](https://kbdfans.myshopify.com/)
+Hardware Availability: [KBDFans](https://kbdfans.myshopify.com/products/niu-mini-40-diy-kit)
 
 Make example for this keyboard (after setting up your build environment):