This feature now works for entity instantiations. It does not work for component instantiations or procedure calls. Leaving this open to remind me to implement those.
This question is only tangentially related to this issue, but I thought I would ask.
Is it within the scope of this project to implement compete entity instantiation snippets? There's a great plug-in for Atom that I would like to replicate in nvim. Maybe it works better as a separate plug-in.