Add documentation for rowAttributesGetter

[pradeepnschrodinger]

Description

Added the prop type definition for rowAttributesGetter in the table component so that it appears in the generated docs.

Motivation and Context

The prop rowAttributesGetter was added along with gridAttributesGetter through #491, but only the latter prop was documented.
Partially fixes #514.

How Has This Been Tested?

Verified that The prop rowAttributesGetter was added along with gridAttributesGetter through #491, but only the latter prop was documented.
Partially fixes #514

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.

[wcjordan]

lgtm