Add missing space in IHostApplicationBuilder description (#43934)

Author: BartoszKlonowski

docs/core/extensions/generic-host.md

@@ -225,7 +225,7 @@ To add host configuration, call <xref:Microsoft.Extensions.Hosting.HostBuilder.C
 
 # [IHostApplicationBuilder](#tab/appbuilder)
 
-App configuration is created by calling <xref:Microsoft.Extensions.Hosting.HostBuilder.ConfigureAppConfiguration%2A> on an <xref:Microsoft.Extensions.Hosting.IHostApplicationBuilder>. The public<xref:Microsoft.Extensions.Hosting.IHostApplicationBuilder.Configuration?displayProperty=nameWithType> property allows consumers to read from or make changes to the existing configuration using available extension methods.
+App configuration is created by calling <xref:Microsoft.Extensions.Hosting.HostBuilder.ConfigureAppConfiguration%2A> on an <xref:Microsoft.Extensions.Hosting.IHostApplicationBuilder>. The public <xref:Microsoft.Extensions.Hosting.IHostApplicationBuilder.Configuration?displayProperty=nameWithType> property allows consumers to read from or make changes to the existing configuration using available extension methods.
 
 # [IHostBuilder](#tab/hostbuilder)