Link CONTRIBUTING.md from the tour

For now it has to be a full link but in the future it would be nice to
open it relatively in the editor.

Author: code-asher

.tours/contributing.tour

@@ -145,7 +145,7 @@
     {
       "file": "ci/dev/vscode.patch",
       "line": 1,
-      "description": "code-server makes use of VS Code's frontend web/remote support. Most of the patch implements the remote server since that portion of the code is closed source and not released with VS Code.\n\nWe also have a few bug fixes and have added some features (like client-side extensions). See CONTRIBUTING.md for a list.\n\nWe make an effort to keep the patch as small as possible."
+      "description": "code-server makes use of VS Code's frontend web/remote support. Most of the patch implements the remote server since that portion of the code is closed source and not released with VS Code.\n\nWe also have a few bug fixes and have added some features (like client-side extensions). See [https://github.com/cdr/code-server/blob/master/doc/CONTRIBUTING.md#vs-code-patch](https://github.com/cdr/code-server/blob/master/doc/CONTRIBUTING.md#vs-code-patch) for a list.\n\nWe make an effort to keep the patch as small as possible."
     }
   ]
 }