Doc edits

[jgabry]

Submission Checklist

• Run unit tests
• Declare copyright holder and agree to license (see below)

Summary

Some edits to the loo method and a few other places

Copyright and Licensing

Please list the copyright holder for the work you are submitting
(this will be you or your assignee, such as a university or company):
Columbia University

By submitting this pull request, the copyright holder is agreeing to
license the submitted work under the following licenses:

• Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
• Documentation: CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

[codecov-commenter]

Codecov Report

Merging #795 (bacbc49) into master (93dd0da) will decrease coverage by 1.72%.
The diff coverage is n/a.

❗ Current head bacbc49 differs from pull request most recent head 7835bc3. Consider uploading reports for the commit 7835bc3 to get more accurate results

@@            Coverage Diff             @@
##           master     #795      +/-   ##
==========================================
- Coverage   88.27%   86.56%   -1.72%     
==========================================
  Files          12       12              
  Lines        4152     4152              
==========================================
- Hits         3665     3594      -71     
- Misses        487      558      +71     

Files Changed	Coverage Δ
R/fit.R	96.22% <ø> (ø)

... and 5 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[jgabry]

Going to merge this since it's just minor doc edits