If your script contains UI elements (that you probably created with the designer), opening directly the .js or .vb file will get you your code and a resource section at the end.
See the code in the first post here : FAYT script : Dynamic Tab Groups
EDIT: I realize you probably don't have UI elements if you created all by yourself (IMHO using ui components is way easier with the resource designer). In that case : no RESOURCES section in your code and no need to copy back to the Opus editor (the one you call RESOURCES). Saving in VSCODE should be enough. That's what I do with sublime text, there's no reason it would be different with another text editor.