Tutor/shell commands

[jerabaul29]

Provide tutor about the "shell command and related" tooling offered by helix: :sh , :insert-output , :pipe , and the likes.

[jerabaul29]

Just a kind reminder on this :) . Any thoughts / comments? @David-Else you have been interested in these "tutor extension" PRs in the past - would be great if you have feedback on this one too :) .

[David-Else]

It looks awesome! Sorry I don't have time to give a full review right now, but I have made some suggestions.

[jerabaul29]

Thanks for the review and your kind words! :) Updated :) .

[jerabaul29]

Not sure who could review / approve this? :) Maybe @pascalkuthe / @the-mikedavis ? :) (sorry if tagging you is too pushy - if so let me know and I wont do it in the future :) taking the liberty to do so here as this is a minor documentation update, so should be quite benign to approve and merge :) ).

[the-mikedavis]

Chapters 14.2 and 14.3 are to tall: each chapter in the tutor should have a fixed height (19 rows I believe, 22 including the header).

I'm wary of adding this much content about shell interaction especially because it's unix specific: in its current form it's not useful to readers on Windows. I think mentioning :sh and maybe :insert-output/:append-output/! is good but we can probably skip the pipe commands or mention them but not go into details: I don't think the tutor should be recommending how to set up scripting since that isn't a basic workflow. We can probably solve the Windows problem by keeping it simple and recommending ls on Unix systems and dir on Windows.