Leaf nodes and submaps are not sorted when pretty-printing choicemaps.

[ztangent]

Currently, pretty-printing for choicemaps does not attempt to sort the addresses of leaf-nodes or submaps before printing them:

Gen.jl/src/choice_map.jl

Lines 126 to 137 in 18c06fd

	for (key, value) in key_and_values
	# For strings, `print` is what we want; `Base.show` includes quote marks.
	# https://docs.julialang.org/en/v1/base/io-network/#Base.print
	print(io, indent_vert_str)
	print(io, (cur == n ? indent_last_str : indent_str) * "$(repr(key)) : $value\n")
	cur += 1
	end
	for (key, submap) in key_and_submaps
	print(io, indent_vert_str)
	print(io, (cur == n ? indent_last_str : indent_str) * "$(repr(key))\n")
	_show_pretty(io, submap, pre + 4, cur == n ? (vert_bars...,) : (vert_bars..., pre+1))
	cur += 1

This leads to confusing output for choicemaps produced by the dynamic modeling language, especially those that involve for loops -- the addresses are not sorted by timesteps, and so it's not as easy to parse what's in the choicemap.

Fixing won't be hard -- we just need to sort the keys before printing, taking care to handle addresses which don't have ordering functions (Base.:<) defined for them.