[ofiwg] descriptive terminology for libfabric

[Hefty, Sean]

> Okay, then is it more accurate to say, "libfabric is an API designed to
> support networking middleware such as MPI and at programming models and
> languages such as PGAS and SHMEM"

Better - there's an extra 'at' before programming models.  I would either insert some commas to help with parsing or reword to something like:

Libfabric is an API designed to support networking middleware, programming models, and languages, such as MPI, SHMEM, and PGAS.