Fixes #3209 - Formalize Cancellable Work Pattern and add helpers (#4092)

docfx/toc.yml

@@ -5,4 +5,21 @@
   href: api/
 
 - name: Source
-  href: https://github.com/gui-cs/Terminal.Gui
+  href: https://github.com/gui-cs/Terminal.Gui
+
+- name: Documentation
+  href: docs/
+  items:
+    - name: Getting Started
+      href: docs/getting-started.md
+    - name: Events Deep Dive
+      href: docs/events.md
+    - name: View Documentation
+      href: docs/View.md
+    - name: Keyboard Handling
+      href: docs/keyboard.md
+    - name: Mouse Support
+      href: docs/mouse.md
+    - name: Showcase
+      href: docs/showcase.md
+    # Add other existing documentation entries as needed