add cookie path

[prabirshrestha]

Not using path in cookies can lead to unexpected behaviors as you may land with the same cookie name but different paths. Updated the example to always use path.

Another option would be default the path to / but not sure if this would cause security issues. .NET does exactly what tide is currently doing. I personally believe there shouldn't be an api to only set name and value for a cookie without domain and path but that is for another discussion. These days I tend to say never to use framework apis for cookies but instead always use the wrapper so it is done in a safe way.

Also updated the example to handle when cookie is not present as the first time I ran it my initial impression was cookie example was broken since .unwrap() was causing crash.