Twig Array to string conversion
You shouldn't really be building complex data structures inside of Twig templates. You can achieve the desired result in a more idiomatic and readable way like this:
{% for status in status_info %}
<a href="{{ status.link }}" title="{{ status.title }}">{{ status.display }}</a>
{% if not loop.last %}|{% endif %}
{% endfor %}
info is an array, so you should simple write
{{ info|join(', ') }}
to display your info array.
[info] is a array with one value : the array info.
You can user json_encode for serialize array as strig, then show pretty - build in twig
{{ array|json_encode(constant('JSON_PRETTY_PRINT')) }}