Support for ASDF version 16

[grossvogel]

Version 16 of ASDF is a backwards-incompatible release and works quite differently: https://asdf-vm.com/guide/upgrading-to-v0-16.html

The main thing I ran into with Lexical is that ASDF no longer seems to ship with a bash activation script at ~/.asdf/asdf.sh, relied upon by Lexical here:

lexical/bin/activate_version_manager.sh

Lines 64 to 76 in 477e8b4

	_try_activating_asdf() {
	local asdf_dir="${ASDF_DIR:-"$HOME/.asdf"}"
	local asdf_vm="$asdf_dir/asdf.sh"
	if test -f "$asdf_vm"; then
	echo >&2 "Found asdf. Activating..."
	# shellcheck disable=SC1090
	. "$asdf_vm"
	return $?
	else
	return 1
	fi
	}

Instead, the instructions simply say to add ~/.asdf/shims to your path, and in my limited local testing an export statement in that _try_activating_asdf does seem at least superficially to fix the issue and allow Lexical to function.

Updated function definition

_try_activating_asdf() {
    local asdf_dir="${ASDF_DIR:-"$HOME/.asdf"}"
    local asdf_vm="$asdf_dir/shims/elixir"

    if test -f "$asdf_vm"; then
        echo >&2 "Found asdf. Activating..."
        # shellcheck disable=SC1090
        export PATH="$asdf_dir/shims:$PATH"
        return $?
    else
        return 1
    fi
}