.NET 5 runtime stack no longer available for Azure Web Apps

[EgorEmeliyanov]

Re: https://github.com/ironmansoftware/universal-docs/blob/master/config/hosting/azure.md#manually-creating-a-web-app

It appears that .NET 5 is no longer a thing in Azure App Services. I tested it on two tenants -- both have only 6, 7, Core 3.1, 4.8 and 3.5. Same with "az webapp list-runtimes". Version 3 is updated to .NET 6, so it's not big deal -- just outdated documentation.

[EgorEmeliyanov]

Also, it's probably worth mentioning in the same section when talking about updating default paths in appsettings.json that backslashes need to be screened with another backslash (\). If you copy the recommended value from the documentation, JSON won't be parsed.