Add generic-host docs to TOC

Author: natemcmaster

docs/docs/advanced/generic-host.md

@@ -1,7 +1,7 @@
 ---
 uid: generic-host
 ---
-# Using Generic Host
+# Integration with Generic Host
 
 The McMaster.Extensions.Hosting.CommandLine package provides support for integrating command line parsing with
 .NET's [generic host](https://docs.microsoft.com/en-us/aspnet/core/fundamentals/host/generic-host).

docs/docs/toc.md

@@ -5,3 +5,4 @@
 # [@-files (Response File Parsing)](xref:response-file-parsing)
 # Advanced concepts
 ## [Dependency Injection](xref:dependency-injection)
+## [Integration with Generic Host](xref:generic-host)