Merge branch 'ralf/valid' into 'gen_proofmode'

rename valid -> emp_valid

See merge request FP/iris-coq!131
3 jobs for gen_proofmode in 13 minutes and 26 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed build-coq.8.7.1 #9774
fp

00:04:51

passed build-coq.8.7.2 #9773
fp-timing

00:04:36

passed build-coq.dev #9772
fp

00:13:24