Tell the user about the asterisk

[YegorStepanov]

trafficstars

Is this written somewhere? Looks pretty used

https://github.com/dotnet/BenchmarkDotNet/blob/f17453cef3a91ac90540dec1dcdee21725def6f8/src/BenchmarkDotNet/Running/UserInteraction.cs#L97-L103

FYI: It's not string.Contains but IEnumerable.Contains, so the input "a*b" or "**" doesn't work (as excepted).