Merging is fine. But yeah, there’s nothing useful in the .pacnew files included in this update, so just delete them.
in a terminal.
cd /etc
sudo rm shells.pacnew
sudo rm hosts.pacnew
sudo rm passwd.pacnew
Will be fine.
You may if you wish, view them first.
In a Terminal
cd /etc
pacdiff -o
That will list them
then in the Terminal
cat <filename>.pacnew
for each one, to view it.