Web Host --> Generic Host links (dotnet#12847)

Author: tdykstra

aspnetcore/fundamentals/servers/httpsys.md

@@ -80,7 +80,7 @@ HTTP.sys delegates to kernel mode authentication with the Kerberos authenticatio
 
 1. A package reference in the project file isn't required when using the [Microsoft.AspNetCore.App metapackage](xref:fundamentals/metapackage-app) ([nuget.org](https://www.nuget.org/packages/Microsoft.AspNetCore.App/)) (ASP.NET Core 2.1 or later). When not using the `Microsoft.AspNetCore.App` metapackage, add a package reference to [Microsoft.AspNetCore.Server.HttpSys](https://www.nuget.org/packages/Microsoft.AspNetCore.Server.HttpSys/).
 
-2. Call the <xref:Microsoft.AspNetCore.Hosting.WebHostBuilderHttpSysExtensions.UseHttpSys*> extension method when building Web Host, specifying any required <xref:Microsoft.AspNetCore.Server.HttpSys.HttpSysOptions>:
+2. Call the <xref:Microsoft.AspNetCore.Hosting.WebHostBuilderHttpSysExtensions.UseHttpSys*> extension method when building the host, specifying any required <xref:Microsoft.AspNetCore.Server.HttpSys.HttpSysOptions>:
 
    [!code-csharp[](httpsys/sample/Program.cs?name=snippet1&highlight=4-12)]
 
@@ -161,7 +161,7 @@ HTTP.sys delegates to kernel mode authentication with the Kerberos authenticatio
 
    An advantage of `UrlPrefixes` is that an error message is generated immediately for improperly formatted prefixes.
 
-   The settings in `UrlPrefixes` override `UseUrls`/`urls`/`ASPNETCORE_URLS` settings. Therefore, an advantage of `UseUrls`, `urls`, and the `ASPNETCORE_URLS` environment variable is that it's easier to switch between Kestrel and HTTP.sys. For more information, see <xref:fundamentals/host/web-host>.
+   The settings in `UrlPrefixes` override `UseUrls`/`urls`/`ASPNETCORE_URLS` settings. Therefore, an advantage of `UseUrls`, `urls`, and the `ASPNETCORE_URLS` environment variable is that it's easier to switch between Kestrel and HTTP.sys.
 
    HTTP.sys uses the [HTTP Server API UrlPrefix string formats](https://msdn.microsoft.com/library/windows/desktop/aa364698.aspx).
 

aspnetcore/host-and-deploy/azure-apps/index.md

@@ -68,10 +68,18 @@ App settings in the Azure Portal permit you to set environment variables for the
 
 When an app setting is created or modified in the Azure Portal and the **Save** button is selected, the Azure App is restarted. The environment variable is available to the app after the service restarts.
 
-When an app uses the [Web Host](xref:fundamentals/host/web-host) and builds the host using [WebHost.CreateDefaultBuilder](/dotnet/api/microsoft.aspnetcore.webhost.createdefaultbuilder), environment variables that configure the host use the `ASPNETCORE_` prefix. For more information, see <xref:fundamentals/host/web-host> and the [Environment Variables Configuration Provider](xref:fundamentals/configuration/index#environment-variables-configuration-provider).
+::: moniker range=">= aspnetcore-3.0"
 
 When an app uses the [Generic Host](xref:fundamentals/host/generic-host), environment variables aren't loaded into an app's configuration by default and the configuration provider must be added by the developer. The developer determines the environment variable prefix when the configuration provider is added. For more information, see <xref:fundamentals/host/generic-host> and the [Environment Variables Configuration Provider](xref:fundamentals/configuration/index#environment-variables-configuration-provider).
 
+::: moniker-end
+
+::: moniker range=">= aspnetcore-2.0 <= aspnetcore-2.2"
+
+When an app builds the host using [WebHost.CreateDefaultBuilder](/dotnet/api/microsoft.aspnetcore.webhost.createdefaultbuilder), environment variables that configure the host use the `ASPNETCORE_` prefix. For more information, see <xref:fundamentals/host/web-host> and the [Environment Variables Configuration Provider](xref:fundamentals/configuration/index#environment-variables-configuration-provider).
+
+::: moniker-end
+
 ## Proxy server and load balancer scenarios
 
 The [IIS Integration Middleware](xref:host-and-deploy/iis/index#enable-the-iisintegration-components), which configures Forwarded Headers Middleware when hosting [out-of-process](xref:host-and-deploy/iis/index#out-of-process-hosting-model), and the ASP.NET Core Module are configured to forward the scheme (HTTP/HTTPS) and the remote IP address where the request originated. Additional configuration might be required for apps hosted behind additional proxy servers and load balancers. For more information, see [Configure ASP.NET Core to work with proxy servers and load balancers](xref:host-and-deploy/proxy-load-balancer).

aspnetcore/tutorials/grpc/grpc-start.md

@@ -111,7 +111,7 @@ info: Microsoft.Hosting.Lifetime[0]
 * *greet.proto*: The *Protos/greet.proto* file defines the `Greeter` gRPC and is used to generate the gRPC server assets. For more information, see [Introduction to gRPC](xref:grpc/index).
 * *Services* folder: Contains the implementation of the `Greeter` service.
 * *appSettings.json*: Contains configuration data, such as protocol used by Kestrel. For more information, see <xref:fundamentals/configuration/index>.
-* *Program.cs*: Contains the entry point for the gRPC service. For more information, see <xref:fundamentals/host/web-host>.
+* *Program.cs*: Contains the entry point for the gRPC service. For more information, see <xref:fundamentals/host/generic-host>.
 * *Startup.cs*: Contains code that configures app behavior. For more information, see [App startup](xref:fundamentals/startup).
 
 ## Create the gRPC client in a .NET console app

aspnetcore/tutorials/razor-pages/razor-pages-start.md

@@ -177,7 +177,7 @@ Contains configuration data, such as connection strings. For more information, s
 
 ### Program.cs
 
-Contains the entry point for the program. For more information, see <xref:fundamentals/host/web-host>.
+Contains the entry point for the program. For more information, see <xref:fundamentals/host/generic-host>.
 
 ### Startup.cs