You’ll fall in love with jruby. We’ve made the helper library so nice to work with. Check it out!
Regarding your original question, whenever I made changes to a rulesdsl file, I got this in my log:
13:15:52.345 [INFO ] [del.core.internal.ModelRepositoryImpl] - Loading model 'test.rules'
I have this log level set on my system
org.openhab │ INFO