doc cleanup

src/main/java/com/gtnewhorizons/postea/api/ItemStackReplacementManager.java

@@ -160,8 +160,7 @@ public class ItemStackReplacementManager {
      *          </ul>
      *
      * @implNote For performance reasons, Postea assumes that the tag that was passed to the handler hasn't been
-     *           modified
-     *           if you return a null value. This isn't enforced though since returning a null value after doing some
+     *           modified if you return false. This isn't enforced though since returning false after doing some
      *           modifications has a couple niche uses. eg: having separate handlers for different migrations of a
      *           single thing that can be sunset at different times down the line.
      *

src/main/java/com/gtnewhorizons/postea/utility/TransformerRegistry.java

@@ -41,11 +41,11 @@ public class TransformerRegistry {
     public static final Int2IntOpenHashMap REMAPPED_IDS = new Int2IntOpenHashMap();
 
     /**
-     * Stores simple item transformations (eg if old id is # with meta # then turn into item with id # with meta #.
+     * Stores simple item transformations (eg if old id is # with meta # then turn into item with id # with meta #.)
      */
     public static final SimpleTransformationMap<Pair<Integer, Short>> SIMPLE_ITEM_TRANSFORMATION_MAP = new SimpleTransformationMap<>();
     /**
-     * Stores simple block transformations (eg if old id is # with meta # then turn into item with id # with meta #.
+     * Stores simple block transformations (eg if old id is # with meta # then turn into item with id # with meta #.)
      */
     public static final SimpleTransformationMap<Pair<Integer, Short>> SIMPLE_BLOCK_TRANSFORMATION_MAP = new SimpleTransformationMap<>();