Merge branch '1.21' into 1.20.3

Author: SkyDynamic

common/src/main/java/io/github/skydynamic/quickbackupmulti/utils/BackupManager.java

@@ -134,7 +134,7 @@ public static void makeBackup(CommandSourceStack commandSource, String name, Str
         try {
             commandSource.sendSystemMessage(Component.nullToEmpty(tr("quickbackupmulti.make.start")));
             MinecraftServer server = commandSource.getServer();
-            server.executeIfPossible(() -> server.saveEverything(true, true, true));
+            server.executeBlocking(() -> server.saveEverything(true, true, true));
             for (ServerLevel serverLevel : server.getAllLevels()) {
                 if (serverLevel == null || serverLevel.noSave) continue;
                 serverLevel.noSave = true;