show handles of users that reacted to issues and pulls #636

I chose an arbitrary cutoff of 20 usernames to display

I have a different implementation separating username resolving from service layer. I'll open a separate PR soon

Actually nvm. This seems fine.

The benefit of (2) being that if there are a lot of reacts, we aren't querying all of them from the db. so it's probably preferable to make two separate small db calls than 1 unbounded one

thanks for the PR! this works like a charm, couple of nits:

• can we avoid hardcoding maxUsersPerKind in the db module? we can just return all the users here or accept a limit parameter.
• instead of a custom tooltip, can we use the title attribute? this has the added benefit of being accessible! something like this might work:

        {{ if gt (length .Users) 0 }}
          title="{{ range $i, $did := .Users }}{{ if ne $i 0 }},{{end}} {{ resolve . }}{{ end }}"
        {{ else }}
          title="{{ .Kind }}"
        {{ end }}

• lastly, the the repo/fragments/reaction fragment is broken in two scenarios: when it is rendered from either of the endpoints in state/reaction.go, this is because Users is not passed in. the rendering itself is fine, but there is a latent error in rendering the template. hovering over a reaction right after you react will not show the tooltip. a refresh will be necessary.

Thank you for the review @opp.li ! Addressed, I believe