## What changes were proposed in this pull request?

Fixing three small typos in the docs, in particular:

It take a `RDD` -> It takes an `RDD` (twice)

It take an `JavaRDD` -> It takes a `JavaRDD`

I didn't create any Jira issue for this minor thing, I hope it's ok.

## How was this patch tested?

visually by clicking on 'preview'

Author: Jirka Kremser <jkremser@redhat.com>

Closes #20108 from Jiri-Kremser/docs-typo.