Fix rendering of emoji when doing a merge.

Without this, we would typically get

```
Plan: 3 to add, 0 to change, 0 to destroy.:twisted_rightwards_arrows: Upstream was modified, a new merge was performed.
```

With this, we should be getting whitespace before the
`:twisted_rightwards_arrows` part.

server/events/templates/plan_success_wrapped.tmpl

@@ -23,6 +23,6 @@ This plan was not saved because one or more projects failed and automerge requir
   {{ .RePlanCmd }}
   ```
 {{ end -}}
-{{ .PlanSummary -}}
+{{ .PlanSummary }}
 {{ template "mergedAgain" . -}}
 {{ end -}}