Integrate confidence intervals with `total`

[smishr]

To integrate _ci function with total. See #190 for exemplar integration with mean, and keep consistency.

• total with confidence interval options
• Add docstrings
• Add doctests

[nadiaenh]

I'm assuming I should build onto the work from #190 (e.g. add to ci.jl) but that PR is not merged yet. Should I push to smishr/Survey.jl when I'm done ?

[smishr]

I'm assuming I should build onto the work from #190 (e.g. add to ci.jl) but that PR is not merged yet. Should I push to smishr/Survey.jl when I'm done ?

I think rn we have paused working on CI until we confident on the data structure changes, if any.

But for future reference, I think you are able to clone and checkout the PR branch locally (using Github Desktop or git CLI), and continue work from there and push changes.

If above doesnt work, we can merge the PR and you can create new branch from it, and do the others in separate PRs (best option imo)

Or you may do what you suggested above. Another option would be to copy paste all the code into a newly created local branch, and continue work there. The old PR would be