Clarify what "Remove" does in the check for change requests must be approved

Proposal

Clarify what "Remove" does in the merge check that change requests must be approved.

Consider:

1. Adding tooltip to the "Remove" button to explain functionality

Background

@clavimoniere reported that it is unclear what "Remove" means: does it mean removing the change request or remove the current person as a reviewer?

Investigate

1. What is behavior when there are two change requests, do we see two "Remove" buttons?