The registry entries mentioned in the article are already empty, the files either don't exist or are 0 bytes long. IEcacheview doesn't show me any entries.
The Delphi code posted does indeed clear the "autocomplete" history. I still don't know where/how that information is saved, but I don't care as long as it is gone.
If executed a second time with no autocomplete entries present it will loop indefinitely, but you can Ctrl-C out of it.