remove unsused code, reformat touched code, add info where patch cannot be applied
Primary purpose is to show which patch raise NameError
=> it happened a lot when someone patching something non-existence or deactivated...
- we dropped Redmine-compatibiles with v10
- remove HTML formatting = v11+ have only CKeditor and no option to change it
- require ruby 2.7+
Edited by Lukáš Pokorný