examples, oneshot services rework

Signed-off-by: fbt <fbt@fleshless.org>

README.md

@@ -8,6 +8,9 @@ Services
 A service is a script in the ssm's init.d directory.  
 By default it's /etc/ssm/services for system services and $XDG_CONFIG_HOME/ssm/services for user ones.
 
+Note that they are BASH scripts that get sourced by `ssm`. Same pitfalls apply.
+Hopefully, you won't have to do complex logic in the services.
+
 ## Global settings
 
 * `cgroups = 0` — Enable cgroup-related features.
@@ -41,4 +44,4 @@ Optional settings (incomplete list):
 * `service_oneshot = no` — The service is supposed to do something and die instead of daemonizing.
 * `service_signals_passthru` — Array, empty by default. Which signals should the svc pass directly to the service mainpid. This is dangerous, use with caution.
 
-Quote your expansions btw. This is still BASH.
+Mind your expansions.