[mpiwg-sessions] follow up to a TODO from last WG meeting

Hi Folks, I had a todo item from last, namely track down when a sentence vanished from the chap-dynamic chapter. Turns out it was a mistake in the pythonization commit. See https://github.com/mpi-forum/mpi-issues/issues/289 I’ll open a PR to put the sentence back in. Howard -- Howard Pritchard HPC-ENV Los Alamos National Laboratory