* Re-align docs with code example for mnist

* Also fix dist_mnist and add context highlight

* [doc] Fix code snippet in derive-for-training

* Fix another code snippet in derive-for-training

Also the ONNX how to import file was tested and it was discovered
that the wheel was actually output to a different directory than
the one specified.

* WIP editing so far for review and feedback

* Add missing env var export for neon install new process

* Add modified venv setup for TF

* More edits for FW integration and landpage

* Revise from PR feedback

* More PR feedback and editing for clarity

* Minor rewording, clearer explanation

* Final pass edit

* more editing

* More extensive examples of graph building.

* Review comments

* Review comments

* Review comments