Construct the maximum-likelihood tree module descriptor
Source:R/module_remaining_registry.R
ml_tree_module_spec.RdA genuine maximum-likelihood alternative to the "tree" module's neighbour-joining tree, distinct from it (not a replacement): GTR+Gamma with Lewis (2001) ascertainment-bias correction, via the optional `phangorn` package. Individual-level only – ML substitution models operate on per-taxon sequence characters, which have no standard, defensible analogue at the population-allele-frequency level the "population_tree" module operates at. Off by default: heavier than the NJ tree and depends on an optional package.