Add imports on all the pages in documentation

[umararshad4]

Feature and motivation

add the imports on all the pages in the documentation not just the 1 2 line of code.

[diemol]

Can you give a more concrete example? We are in the process of linking all code examples to GitHub files, so when people click on the example they will be able to see all the code.

[titusfortner]

There is a link at the bottom of each code snippet that will take you to the github page that includes *all the code, imports, setup, assertions, etc. We want to keep the docs themselves readable by only including the relevant portion. If the link isn't obvious, maybe we can make it more promenant.