Fix typo in SignalR tutorial for folder name

Fixed Typo in VSCode command in the Terminal when opening the SignalRChat folder name, the document has `SignalRChat1 instead of `SignalRChat as the folder name.

Author: marcusbello

aspnetcore/tutorials/signalr.md

@@ -78,7 +78,7 @@ code -r SignalRChat
 
 The `dotnet new` command creates a new Razor Pages project in the `SignalRChat` folder.
 
-The `code` command opens the `SignalRChat1 folder in the current instance of Visual Studio Code.
+The `code` command opens the `SignalRChat folder in the current instance of Visual Studio Code.
 
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