
Load a classification
resy_load_expert.RdLoads a parsed expert-system object ready for use with [resy_classify()].
If `expertfile` is given it takes precedence over `scheme`/`version`. The file format is detected from the extension:
- `.json`
Parsed directly via the internal JSON parser (preferred).
- `.txt`
Parsed via the legacy text parser.
When no `expertfile` is supplied, the function looks for `expert.json`, then `expert.txt` (in that order) under `inst/extdata/classifications/<scheme>/<version>/` in the installed package.