Define `log1p` and `expm1` as acting on OP-chains

Amend the operator section as well to make both functions also work on
chains of operators.
9 jobs for fix_op_expm1 in 8 minutes and 9 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build Docker
passed #971240
build_docker_from_cache

00:00:23

 
  Test
passed #971242
test_mpi

00:05:24

passed #971241
test_serial

00:06:06

82.0%
 
  Demo Runs
passed #971247
run_bernoulli

00:00:39

passed #971248
run_curve_fitting

00:00:37

passed #971244
run_getting_started_1

00:00:44

passed #971245
run_getting_started_2

00:01:08

passed #971246
run_getting_started_3

00:01:17

passed #971243
run_ipynb

00:01:39