Add hover tip for +1 and -1 emoji on merge request listing

Description

Currently the merge request listing shows a count of 👍 and 👎 votes which have been applied. However, there is no easy way to see who applied these.

Proposal

It would be very helpful (specifically time saved) if users could hover over the 👍 or 👎 votes which appear on the merge request listing to see a hover tip with the names of users who applied that specific emoji. I am specifically thinking about the following: