If you're on 8.1.19 or higher, project library scripts with "docstrings" per Python convention do show up in the autocomplete in other editors:
https://docs.inductiveautomation.com/display/DOC81/Scripting+in+Ignition#ScriptinginIgnition-SystemFunctions,Hints,andAutocomplete
If you're on 8.1.32 or higher, if you author those docstrings according to Google's Python style guide, you'll even get nice argument and return value descriptions.