Update hosting shutdown doc (dotnet#56176)

src/libraries/Microsoft.Extensions.Hosting/docs/HostShutdown.md

@@ -25,10 +25,12 @@ This would allow for the clean up code in the application to run - for example,
 `Host.Run` in the Main method.
 
 This caused other issues because SIGTERM wasn't the only way `ProcessExit` was raised. It is also raised by code
-in the application calling `Environment.Exit`. `Environment.Exit` isn't a graceful way of shutting down a process.
-It raises the `ProcessExit` event and then exits the process. The end of the Main method doesn't get executed. However,
-since ConsoleLifetime blocked `ProcessExit` waiting for the Host to shutdown, this behavior also lead to [deadlocks][deadlocks]
-due to `Environment.Exit` also blocking waiting for `ProcessExit` to return. Additionally, since SIGTERM handling was attempting
+in the application calling `Environment.Exit`. `Environment.Exit` isn't a graceful way of shutting down a process
+in the `Microsoft.Extensions.Hosting` app model. It raises the `ProcessExit` event and then exits the process. The end of the
+Main method doesn't get executed. Background and foreground threads are terminated. `finally` blocks are not executed.
+
+Since ConsoleLifetime blocked `ProcessExit` waiting for the Host to shutdown, this behavior lead to [deadlocks][deadlocks]
+due to `Environment.Exit` also blocking waiting for `ProcessExit` to return. Additionally, since the SIGTERM handling was attempting
 to gracefully shut down the process, ConsoleLifetime would set the ExitCode to `0`, which [clobbered][clobbered] the user's
 exit code passed to `Environment.Exit`.
 
@@ -42,6 +44,11 @@ has logic to handle scenario (5) above. Apps that call `Environment.Exit`, and n
 
 [POSIX signals]: https://github.com/dotnet/runtime/issues/50527
 
+If your application uses Hosting, and you want to gracefully stop the host, you can call
+[`IHostApplicationLifetime.StopApplication()`][StopApplication] instead of `Environment.Exit`.
+
+[StopApplication]: https://docs.microsoft.com/dotnet/api/microsoft.extensions.hosting.ihostapplicationlifetime.stopapplication
+
 ### Hosting Shutdown Process
 
 The following sequence model shows how the signals in (4) above are handled internally in the Hosting code. It isn't necessary