fix(alpine): restart_xray uses rc-service; OpenRC reload reads pidfile contents

`14. Restart Xray` failed on Alpine with `systemctl: command not found` —
restart_xray was the only service action missing an Alpine branch. While
fixing it, the OpenRC reload action was passing the pidfile path to `kill`
instead of the PID inside it, so `rc-service x-ui reload` would have
failed too.

x-ui.rc

@@ -13,6 +13,6 @@ start_pre(){
 }
 reload() {
   ebegin "Reloading ${RC_SVCNAME}"
-  kill -USR1  $pidfile
+  kill -USR1 $(cat $pidfile)
   eend $?
 }

x-ui.sh

@@ -436,7 +436,11 @@ restart() {
 }
 
 restart_xray() {
-    systemctl reload x-ui
+    if [[ $release == "alpine" ]]; then
+        rc-service x-ui reload
+    else
+        systemctl reload x-ui
+    fi
     LOGI "xray-core Restart signal sent successfully, Please check the log information to confirm whether xray restarted successfully"
     sleep 2
     show_xray_status