Removing assignee is uninformative

Problem

I cannot see which assignee I removed.

Usecase

I accidentally removed the (single) assignee from an issue.. the system note didn't help me out.

Proposal

Should state which assignee is unassigned 😉

Design

CC/Call to actions

@victorwu @smcgivern (assigned this gitlab-ce~2311884 , but can almost be considered a bug I think) @ClemMakesApps (as you implemented the multiple assignee feature)