Add in style guidelines on writing shell documentation as per isuse #…

Created by: seamuslee001

…#190 (closed) proposal

ping @totten @MegaphoneJon @seanmadsen @nganivet I think Sean's latest proposal on this issue is good so have written documentation based on that but if we need more discussion best go on the issue

Created by: seancolsen

I like this. Will wait to merge until we have more approvals from others.

Created by: nganivet

+1, very sound and clearly written.

Created by: MegaphoneJon

This sounds good.

Created by: seamuslee001

@seanmadsen seems like we have consensus here