## What changes were proposed in this pull request?
Remove duplicated periods at the end of some sharedParams in ScalaDoc, such as [here](https://github.com/apache/spark/pull/11344/files#diff-9edc669edcf2c0c7cf1efe4a0a57da80L367)
cc mengxr srowen
## How was this patch tested?
Documents change, no test.

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #11344 from yanboliang/shared-cleanup.