GitHub Action CI: Add Go source file format check (#6090)

https://github.com/XTLS/Xray-core/pull/6057#issuecomment-4364819830

And https://github.com/XTLS/Xray-core/pull/6149#issuecomment-4546876261

app/router/command/command.go

@@ -58,7 +58,6 @@ func (s *routingServer) AddRule(ctx context.Context, request *AddRuleRequest) (*
 		return &AddRuleResponse{}, bo.AddRule(request.Config, request.ShouldAppend)
 	}
 	return nil, errors.New("unsupported router implementation")
-
 }
 
 func (s *routingServer) RemoveRule(ctx context.Context, request *RemoveRuleRequest) (*RemoveRuleResponse, error) {