Page not found errors

[masaeokada]

I found that "page not found"errors occurred in the following three places on main website of Node-RED.

1. https://nodered.org/docs/platforms/windows
   
2. https://nodered.org/docs/user-guide/messages#working-with-json
   
3. https://nodered.org/docs/creating-nodes/packaging
   I think that these URL of the websites were changed.