add a copy button next to long commands

[vinyar]

url: https://docs.chef.io/install_server.html

Feature request:
It would be nice if there was a copy button next to the fields which are too long.

[vinyar]

A fantastic super exactly example of what would be mega delightful to see on a chef docs site can be seen here:
https://azure.microsoft.com/en-us/documentation/articles/resource-group-authenticate-service-principal/#authenticate-service-principal-with-password---azure-cli