Nuget.exe push needs a helpful error message for timeout

[dagood]

Using NuGet.exe 3.4.0.665, when I do a NuGet push that hits the default 5 minute timeout I get the following error:

A task was canceled.

Adding the -verbosity Detailed argument, I get this:

System.AggregateException: One or more errors occurred. ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
--- End of inner exception stack trace ---
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
at NuGet.CommandLine.Command.Execute()
at NuGet.CommandLine.Program.MainCore(String workingDirectory, String[] args)

---> (Inner Exception #0) System.Threading.Tasks.TaskCanceledException: A task was canceled.<---

Upgrading from 3.4.0.335 to 3.4.0.665, I didn't know about the -timeout argument so I had to notice that the push was failing at the 5 minute mark then figure out why that would be. This error message should be made clearer and mention the -timeout argument.

/cc @weshaggard