Whenever I update my QuickLook thumbnail/preview generator, I need to wait up to a minute for quicklookd to be automatically restarted before I can see the change.
$ qlmanage -m
...
generators change detected: quicklookd will restart soon
Is there a way to trigger quicklookd restart manually without having to wait for it to automatically restart?
You should use qlmanage -r to manually reset Quick Look Server and all Quick Look client's generator cache.
Sometimes relaunching Finder (press cmd on Finder > Relaunch) also helps as you wont see immediate changes if the finder View hasn't changed and you just preview files.