enhance: allow auto-closing PRs from PRs (#39393)

On GitHub, one can close PRs via `Fixes: #123` references which was not
possible on Gitea before, but now is. Verified fully that behaviour
matches GH and ensured no regressions for external trackers.

modules/references/references.go

@@ -85,6 +85,7 @@ type IssueReference struct {
 	Index   int64
 	Owner   string
 	Name    string
+	IsPull  bool
 	Action  XRefAction
 	TimeLog string
 }
@@ -123,6 +124,7 @@ func rawToIssueReferenceList(reflist []*rawReference) []IssueReference {
 			Index:   r.index,
 			Owner:   r.owner,
 			Name:    r.name,
+			IsPull:  r.isPull,
 			Action:  r.action,
 			TimeLog: r.timeLog,
 		}