Allow listing languages, setting source language (#192)

[akkoma] / test / fixtures / tesla_mock / status.alpicola.com_host_meta

<?xml version="1.0" encoding="UTF-8"?>
<XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0"><hm:Host xmlns:hm="http://host-meta.net/xrd/1.0">status.alpicola.com</hm:Host><Link rel="lrdd" template="https://status.alpicola.com/main/xrd?uri={uri}"><Title>Resource Descriptor</Title></Link></XRD>