Filezilla autodetects when local files are updated and uploads them if a connection is open. I don't know if it works the same way as winscp, though.
You could also, of course, just run a frequent rsync loop in the background. That way, it would check the file every (for instance) minute to see if it's different than on the server, and it'd upload it if so. For a little more elegance, you could do something similar to "http://www.danplanet.com/blog/2012/05/09/low-latency-continuous-rsync/", though that requires some playing around with scripting and installing apps that I'm not personally familiar with. There are other apps (like tsync) that handle transparent synchronization in both directions, but I usually find that a bit of overkill.
Or you could mount the server-side directory over ssh and just edit the file directly. This'd be with, for instance, ssh:
mkdir /home/injurai/localtest
sshfs -o reconnect -o workaround=all -o follow_symlinks -C example.com:/home/injurai/test /home/injurai/localtest
After doing the above (if sshfs is installed and you have all the right keys in the right places), your server directory will be mounted on "/home/injurai/localtest". The "-o reconnect -o workaround=all -o follow_symlinks -C" part is optional.
Mind, if you find an editor that you particularly like, it couldn't hurt to see if it supports a direct connection. Kate, kwrite, gedit, and UltraEdit happen to do this best I can tell, and I suspect others do as well. Granted, I know you wanted to maximize your editor selection, and looking for editors that limit the selection kind of goes against that criteria, but I figured I'd mention it for completeness.