Add new R functions to the pkgdown R docs website

[exalate-issue-sync]

For some reason, we have to add the new R functions manually to the [pkgdown website|http://docs.h2o.ai/h2o/latest-stable/h2o-r/docs/reference/index.html]. I am not sure if there's a way to get this to automatically update (it's certainly worth looking into), but in the past, we have had to add them manually.

A user pointed out that none of the new [h2o.explain functions|http://docs.h2o.ai/h2o/latest-stable/h2o-docs/explain.html] are on the pkgdown website. I am guessing that there are more functions that we have added since Angela left that have not made it on the website.

Let's add all the new explain/plotting functions and see if there are other new R functions that are missing from the R docs pkgdown website.

[h2o-ops]

JIRA Issue Migration Info

Jira Issue: PUBDEV-7903
Assignee: hannah.tillman
Reporter: Erin LeDell
State: Resolved
Fix Version: 3.36.0.1
Attachments: N/A
Development PRs: Available

Linked PRs from JIRA

#5150