Add vision TOC file.

PiperOrigin-RevId: 505129465

Author: MarkDaoust

site/en/guide/_toc.yaml

@@ -109,10 +109,7 @@ toc:
 - title: "TFModels - NLP"
   path: /tfmodels/nlp
   status: external
-- title: "Example: Image classification"
-  path: /tfmodels/vision/image_classification
-- title: "Example: Object Detection"
-  path: /tfmodels/vision/object_detection
+- include: /tfmodels/vision/_toc.yaml
 
 - heading: "Estimators"
   status: deprecated