Add lemma `map_subseteq_inv`.

2 jobs for !335 with robbert/map_subseteq_inv in 7 minutes and 9 seconds (queued for 5 seconds)
latest detached
Status Name Job ID Coverage
  Build
passed build-coq.8.10.2 #157896
fp

00:04:47

passed build-coq.8.13.2-mr #157895
fp

00:07:09