Breadcrumb_path is an absolute path of toc.json

breadcrumb_path is an absolute path by removing host. That means you can just append host name to visit that file. Like following shows: https://review.docs.microsoft.com/en-us/visualstudio/_breadcrumb/toc.json
Although sometimes relative path can work, however, we doesn't suggest user to use that way.

Author: fenxu

docs/docfx.json

@@ -35,7 +35,7 @@
       "feedback_system": "GitHub",
       "feedback_github_repo": "MicrosoftDocs/visualstudio-docs",
       "feedback_product_url": "https://developercommunity.visualstudio.com/",
-      "breadcrumb_path": "~/_breadcrumb/toc.yml",
+      "breadcrumb_path": "/visualstudio/_breadcrumb/toc.json",
       "ROBOTS": "INDEX,FOLLOW",
       "author": "",
       "ms.author": "",