remove extra slash in VS release notes URL (#16733)

Author: scottaddie

docs/whats-new/index.yml

@@ -55,7 +55,7 @@ landingContent:
           - text: C# compiler (Roslyn) release notes
             url: https://github.com/dotnet/roslyn/tree/master/docs/ide
           - text: Visual Studio release notes
-            url: https://docs.microsoft.com//visualstudio/releases/2019/release-notes
+            url: https://docs.microsoft.com/visualstudio/releases/2019/release-notes
           - text: Visual Studio for Mac release notes
             url: https://docs.microsoft.com/visualstudio/releasenotes/vs2019-mac-relnotes
           - text: Visual Studio Code release notes