Expand spawn command syntax and improve tab completion

Updated the spawn command to require an additional <mob> argument. Enhanced the tab completion functionality to provide context-sensitive suggestions based on the number of arguments.

src/main/java/com/alttd/custommobs/config/Messages.java

@@ -28,7 +28,7 @@ public class Messages extends AbstractConfig {
 
         public static String HELP_MESSAGE_WRAPPER = "<gold>Main help:\n<commands></gold>";
         public static String HELP_MESSAGE = "<green>Show this menu: <gold>/cm help</gold></green>";
-        public static String SPAWN = "<green>Spawn a mob of a specific type: <gold>/cm spawn <mob_type> [<world> <x> <y> <z>]</gold></green>";
+        public static String SPAWN = "<green>Spawn a mob of a specific type: <gold>/cm spawn <mob_type> <mob> [<world> <x> <y> <z>]</gold></green>";
 
         @SuppressWarnings("unused")
         private static void load() {

src/main/java/com/alttd/custommobs/config/MobTypes.java

@@ -43,6 +43,10 @@ public class MobTypes extends AbstractConfig {
             return Optional.of(MOB_TYPES.get(name));
         }
 
+        public static List<String> getAllMobTypes() {
+            return MobTypes.MOB_TYPES.MOB_TYPES.keySet().stream().toList();
+        }
+
         @SuppressWarnings("unused")
         private static void load() {
             MOB_TYPES.clear();