Template grammar issue in comment for auth options

[Eilon]

Here:

https://github.com/aspnet/AspNetCore/blob/master/src/ProjectTemplates/Web.ProjectTemplates/content/StarterWeb-CSharp/Startup.cs#L107

                    // If your application needs to do authenticate single users, add your user validation below.

Should probably be:

                    // If your application needs to authenticate single users, add your user validation below.