Bulgarian translation updated by Ivan Cenov (#11799)
Filling locales (#6965).
Do not copy subtasks twice when copying an issue and its descendants (#6965).
Adapt subtasks copy when copying a project (#6965).
Option to copy subtasks when copying issue(s) (#6965).
gantt: code layout cleanup html days headers
gantt: code layout cleanup html weeks headers
gantt: use content_tag instead of html tag at days headers
gantt: use content_tag instead of html tag at gantt header outline
gantt: code layout cleanup ruby code at head of show.html.erb
