Add precision about wildcard (*) + Redis SignalR Backplane = Pattern based subscriptions

**When the group name contains wildcard, Redis backplane behavior changes and switch to pattern based subscription**

**This behavior is undocumented (neither in MS code or in this page) and should be :)**

If you check here:
https://github.com/StackExchange/StackExchange.Redis/blob/ae6419a164600b4b54dd7ce8a699efe8e98d8f1c/src/StackExchange.Redis/RedisSubscriber.cs#L162
You see that the behavior (`SUBSCRIBE` vs `PSUBSCRIBE`) changes depending on `IsPatternBased`
Which itself depends upon the Channel mode:
https://github.com/StackExchange/StackExchange.Redis/blob/ae6419a164600b4b54dd7ce8a699efe8e98d8f1c/src/StackExchange.Redis/RedisChannel.cs#L43

Which in the case of Redis backplane is left unset (=Auto)

There does not seem to be a way to override this behavior with a backplane setting.

This happened to me, so I did a very basic escaping to resolve this issue (`groupName.Replace("*", "§")`)

**Maybe it would be a good idea to also have a setting and set it to false by default** (the wildcard behavior might be desired in some cases, but probably just biting some users like me...)

Thank you

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#### Document Details

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* ID: c548355c-d88f-b941-0622-56732973123b
* Version Independent ID: bddd7575-422d-4342-af48-f6b0979fb69a
* Content: [Redis backplane for ASP.NET Core SignalR scale-out](https://learn.microsoft.com/en-gb/aspnet/core/signalr/redis-backplane?view=aspnetcore-7.0)
* Content Source: [aspnetcore/signalr/redis-backplane.md](https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/signalr/redis-backplane.md)
* Product: **aspnet-core**
* Technology: **aspnetcore-signalr**
* GitHub Login: @bradygaster
* Microsoft Alias: **bradyg**