References to React are misleading

[nickserv]

We still seem to suggest that this library is only for React in some places, when it's meant to be general purpose for any testing library.

Thanks to @gndelia for discovering most of these issues!

• it only lists React in the summary

• All the examples are of React in the Readme - not dom related

The docs state

user-event is a companion library for React Testing Library that provides...

[ph-fritsche]

Updated docs:

While most examples with user-event are for React, the library can be used
with any framework as long as there is a DOM.

Updated repo info: