Update .NET Core SDK URL

package.json

@@ -398,7 +398,7 @@
         "csharp.suppressDotnetInstallWarning": {
           "type": "boolean",
           "default": false,
-          "description": "Suppress the warning that the .NET SDK is not on the path."
+          "description": "Suppress the warning that the .NET Core SDK is not on the path."
         },
         "csharp.unitTestDebuggingOptions": {
           "type": "object",

src/coreclr-debug/activate.ts

@@ -90,7 +90,7 @@ function showDotnetToolsWarning(message: string): void {
         vscode.window.showErrorMessage(message,
             goToSettingsMessage, getDotNetMessage).then(value => {
                 if (value === getDotNetMessage) {
-                    let dotnetcoreURL = 'https://dotnet.microsoft.com/download';
+                    let dotnetcoreURL = 'https://dot.net/core-sdk-vscode';
 
                     vscode.env.openExternal(vscode.Uri.parse(dotnetcoreURL));
                 } else if (value === goToSettingsMessage) {