README: Update list of supported APIs / backends

[travelynx](https://finalrewind.org/projects/travelynx/) allows checking into

individual public transit vehicles (e.g. buses, ferries, trams, trains) across

most of Germany, Switzerland, Austria, Luxembourg, Ireland, and parts of the

USA. Thus, it provides a log of your railway journeys annotated with real-time

delays and service messages, if available. It supports german railways and

trains exposed by the Deutsche Bahn [IRIS

Interface](https://finalrewind.org/projects/Travel-Status-DE-IRIS/) as well as

regional and local transit exposed by supported [HAFAS

Instances](https://finalrewind.org/projects/Travel-Status-DE-HAFAS/).  Support

for EFA instances and bahn.de is under way.

most of Germany, Switzerland, Austria, Luxembourg, Ireland, Denmark, and parts

of the USA. Thus, it provides a log of your railway journeys annotated with

real-time delays and service messages, if available. It supports German

long-distance, regional and local transit exposed by the Deutsche Bahn [bahn.de

interface](https://finalrewind.org/projects/Travel-Status-DE-DBRIS/), a variety

of [EFA](https://finalrewind.org/projects/Travel-Status-DE-VRR/) and

[HAFAS](https://finalrewind.org/projects/Travel-Status-DE-HAFAS/) interfaces,

andt [MOTIS](https://finalrewind.org/projects/Travel-Status-MOTIS/) APIs

including the [transitous](https://transitous.org/) aggregator.

You can use the public instance on [travelynx.de](https://travelynx.de) or

host your own. Further reading: