Simplify Argument.tabCompleteSupplier

SpigotCore_Main/src/de/steamwar/command/Argument.java

@@ -117,9 +117,7 @@ public class Argument<T> {
                 // Check number constraints if needed
                 if (argumentType.number && !constraint.test(argumentMapped)) return Optional.empty();
             }
-            List<String> strings = Arrays.stream(tabCompletes.apply(s)).filter(t -> t.startsWith(s)).collect(Collectors.toList());
-            if (strings.isEmpty()) strings.add(s);
-            return Optional.of(strings);
+            return Optional.of(Arrays.stream(tabCompletes.apply(s)).filter(t -> t.startsWith(s)).collect(Collectors.toList()));
         } catch (NumberFormatException e) {
             return Optional.empty();
         } catch (Exception e) {

SpigotCore_Main/src/de/steamwar/command/SWCommandBundle.java

@@ -59,8 +59,7 @@ public class SWCommandBundle {
     public List<String> tabComplete(String[] args) {
         List<String> strings = new ArrayList<>();
         for (SWCommand swCommand : swCommandList) {
-            Optional<List<String>> tabCompletes = swCommand.tabComplete(args);
-            if (tabCompletes.isPresent()) strings.addAll(tabCompletes.get());
+            swCommand.tabComplete(args).ifPresent(strings::addAll);
         }
         return strings;
     }