Testing new emoji system using #18679 as a guinea PR

Stream: PR reviews

[Damiano Testa]

#18679 is not intended for merging: I am using it to test the new script for reacting to bors delegate actions.

[Damiano Testa]

#19491 should be a fix for the current action.

[Damiano Testa]

I am not sure whether merging the PR is expected to add a merged reaction to the previous message, but we will see! :smile: