BlockComment is an Xcode source editor extension. It allows you to comment using /* and */ or remove comment of this style easily.
You can also assign it a hot key, "command + control + /" is recommended, with no conflicts to others.
1. Run the application at lease once, then close it.
2. Go to System Preferences -> Extensions -> Xcode Source Editor and enable this extension
3. Reopen Xcode and you can find this extension from Xcode menu.