Add suggestions for items.

worldedit-core/src/main/java/com/sk89q/worldedit/extension/factory/parser/DefaultItemParser.java

@@ -21,6 +21,7 @@ package com.sk89q.worldedit.extension.factory.parser;
 
 import com.sk89q.worldedit.WorldEdit;
 import com.sk89q.worldedit.blocks.BaseItem;
+import com.sk89q.worldedit.command.util.SuggestionHelper;
 import com.sk89q.worldedit.extension.input.InputParseException;
 import com.sk89q.worldedit.extension.input.ParserContext;
 import com.sk89q.worldedit.internal.registry.InputParser;
@@ -39,11 +40,7 @@ public class DefaultItemParser extends InputParser<BaseItem> {
 
     @Override
     public Stream<String> getSuggestions(String input) {
-        if (input.indexOf(':') == -1) {
-            input = "minecraft:" + input;
-        }
-        String key = input;
-        return ItemType.REGISTRY.keySet().stream().filter(s -> s.startsWith(key));
+        return SuggestionHelper.getNamespacedRegistrySuggestions(ItemType.REGISTRY, input);
     }
 
     @Override
@@ -54,7 +51,9 @@ public class DefaultItemParser extends InputParser<BaseItem> {
             try {
                 String[] split = input.split(":");
                 ItemType type;
-                if (split.length == 1) {
+                if (split.length == 0) {
+                    throw new InputParseException("Invalid colon.");
+                } else if (split.length == 1) {
                     type = LegacyMapper.getInstance().getItemFromLegacy(Integer.parseInt(split[0]));
                 } else {
                     type = LegacyMapper.getInstance().getItemFromLegacy(Integer.parseInt(split[0]), Integer.parseInt(split[1]));