FileTypeManager.getInstance().addFileTypeListener() has been deprecated
javadoc: "Subscribe to #FILE_TYPES on any message bus level."
i didn't manage to find what is this message bus and how to use it properly
i assumed that #FILE_TYPES is com.intellij.AppTopics#FILE_TYPES
and message bus is com.intellij.util.messages.MessageBus
but unfortunately the are no javadocs for these staff