Novos easy trinity handler is afaik a precompiled repack.
If you want to edit a source, you have to download the uncompiled sourcecode of trinitycore, modify it and compile it by yourself.
I don't think you have the knowledge to edit it by yourself, so i would just delete all spirit healers and remove the resurrect-spells from the trainers.
You should can do it by yourself - And you know that YOU made it. Just try and play with different things and you'll find out, that you can do much things without touching your code. First steps are always hard but funny.