In some special instance, a mention could get linked and the user would
not really be linked.
This is because of a difference between linking the mention and adding
the user as follower that required a space after the mention.
With this change:
- `[adding mention]@admin [backspace].`: was linked but not added as
follower => now it is not linked either.
- `[adding mention]@admin [backspace][enter][adding mention]@admin `:
the first @admin was linked => now the second is linked
Without the change, added test fails with:
"should not contain a link in the message content"
"should not have linked mention without space"
opw-1934946
closes#31433
Nicolas Lempereur
05533ceda6