Before this change, issuing either
systemctl --user help syncthing[.service]
or
systemctl help syncthing@user[.service]
gave the message
Can't show: http://docs.syncthing.net/
Following this change the syncthing man page is displayed
Systemd Configuration
This directory contains configuration files for running Syncthing under the "systemd" service manager on Linux both under either a systemd system service or systemd user service. For further documentation take a look at the systemd section on http://docs.syncthing.net.