erp5_web_renderjs_ui: provide cancel explanation

7 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

01:07:48

passed ERP5.PerformanceTest-Master

00:24:40

failed ERP5.UnitTest-Master

04:10:36

failed ERP5.UnitTest-Master.Medusa

01:50:04

passed SlapOS.Eggs.UnitTest-Master.Python2

00:11:18

passed SlapOS.Eggs.UnitTest-Master.Python3

00:16:04

passed SlapOS.Eggs.UnitTest-Master.Python3

00:22:29