[SPARK-8927] [DOCS] Format wrong for some config descriptions
[SPARK-8927] [DOCS] Format wrong for some config descriptions

A couple descriptions were not inside `<td></td>` and were being displayed immediately under the section title instead of in their row.

Author: Jonathan Alter <jonalter@users.noreply.github.com>

Closes #7292 from jonalter/docs-config and squashes the following commits:

5ce1570 [Jonathan Alter] [DOCS] Format wrong for some config descriptions

(cherry picked from commit 28fa01e2ba146e823489f6d81c5eb3a76b20c71f)
Signed-off-by: Sean Owen <291c18f3fb7528c712d9098b0e50a515ea0b91d5@cloudera.com>

andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap,andrewor14/iolap