Add mixin implementation

fabric-item-api-v1/src/main/java/net/fabricmc/fabric/mixin/item/TooltipFlagMixin.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.mixin.item;
+
+import org.spongepowered.asm.mixin.Mixin;
+
+import net.minecraft.world.item.TooltipFlag;
+
+import net.fabricmc.fabric.api.item.v1.FabricTooltipFlag;
+
+@Mixin(TooltipFlag.class)
+public interface TooltipFlagMixin extends FabricTooltipFlag {
+}

fabric-item-api-v1/src/main/resources/fabric-item-api-v1.mixins.json

@@ -20,7 +20,8 @@
     "ItemPropertiesMixin",
     "ItemStackMixin",
     "LivingEntityMixin",
-    "ResourceManagerRegistryLoadTaskMixin"
+    "ResourceManagerRegistryLoadTaskMixin",
+    "TooltipFlagMixin"
   ],
   "injectors": {
     "defaultRequire": 1