Updated icon for RazorClassLibrary

src/Microsoft.DotNet.Web.ProjectTemplates/content/RazorClassLibrary-CSharp/.template.config/vs-2017.3.host.json

@@ -11,6 +11,6 @@
     "package": "{0CD94836-1526-4E85-87D3-FB5274C5AFC9}"
   },
   "order": 305,
-  "icon": "vs-2017.3/Empty.png",
+  "icon": "vs-2017.3/RazorClassLibrary.ico",
   "learnMoreLink": "https://go.microsoft.com/fwlink/?linkid=872103"
 }