sulfonate groups not getting captured?

[Aariq]

Needs more investigation but I thought that 3-Aminopropanesulfonate would have a sulfonate group, yet get_fx_groups() does not capture it.

Minimal reproducible example

library(volcalc)
dir <- tempdir()
x <- get_mol_kegg("C03349", dir = dir)
out <- calc_vol(x$mol_path, return_fx_groups = TRUE)
out$sulfonate
#> [1] 0

^{Created on 2023-12-01 with reprex v2.0.2}

[Aariq]

Fixed in #73