improve tutorial

[tlyu]

Add comments to tutorial files so they're easier to follow without
watching the video. Add timestamps from the video to the README.
Add some usages with debugging to demystify the conj-prove examples.

[benjub]

Thanks @tlyu, that's useful ! Why "--|" instead of "--" in somme comments ?

[tlyu]

Thanks @tlyu, that's useful ! Why "--|" instead of "--" in somme comments ?

The --|is a doc comment that adds to the annotations shown when hovering a use of an item. https://github.com/digama0/mm0/blob/master/mm0-hs/mm1.md#doc-comments

[tlyu]

Thanks for the review! I applied your suggestions.