Remove source generators overview

The cookbook, from the roslyn SDK is a better choice.

Author: BillWagner

.openpublishing.redirection.csharp.json

@@ -4052,6 +4052,10 @@
             "source_path_from_root": "/docs/csharp/roslyn/index.md",
             "redirect_url": "/dotnet/csharp/roslyn-sdk/"
         },
+        {
+            "source_path_from_root": "/docs/csharp/roslyn-sdk/source-generators-overview.md",
+            "redirect_url": "https://github.com/dotnet/roslyn/blob/main/docs/features/incremental-generators.cookbook.md"
+        },
         {
             "source_path_from_root": "/docs/csharp/whats-new/tutorials/static-abstract-interface-methods.md",
             "redirect_url": "/dotnet/csharp/whats-new/tutorials/static-virtual-interface-members"

docs/csharp/roslyn-sdk/source-generators-overview.md

@@ -418,8 +418,6 @@ items:
     href: roslyn-sdk/work-with-workspace.md
   - name: Explore code with the syntax visualizer
     href: roslyn-sdk/syntax-visualizer.md
-  - name: Source Generators
-    href: roslyn-sdk/source-generators-overview.md
   - name: Choose diagnostic IDs
     href: roslyn-sdk/choosing-diagnostic-ids.md
   - name: Quick starts