changelog: mention the recent evolve improvements

--HG--
branch : stable
7 jobs for topic/stable/evolve-split-nonlinear in 4 minutes and 59 seconds
Status Name Job ID Coverage
  Test
passed doc #65690

00:00:26

passed flake8 #65684

00:00:34

manual pytype #65685
allowed to fail manual
passed tests-py2-cext #65686

00:04:54

passed tests-py2-pure #65687

00:02:28

passed tests-py3-cext #65688

00:04:59

passed tests-py3-pure #65689

00:03:11