[DOCS][SPARKR] Use verbose names for family annotations in functions.R

## What changes were proposed in this pull request?

- Change current short annotations (same as Scala `group`) to verbose names (same as Scala `groupname`).

    Before:

    ![image](https://cloud.githubusercontent.com/assets/1554276/26033909/9a98b596-38b4-11e7-961e-15fd9ea7440d.png)

    After:
    ![image](https://cloud.githubusercontent.com/assets/1554276/26033903/727a9944-38b4-11e7-8873-b09c553f4ec3.png)

- Add missing `family` annotations.

## How was this patch tested?

`check-cran.R` (skipping tests), manual inspection.

Author: zero323 <zero323@users.noreply.github.com>

Closes #17976 from zero323/SPARKR-FUNCTIONS-DOCSTRINGS.