Clean up the javadoc to pass java 8's doclint

By: Thinkofdeath <thinkofdeath@spigotmc.org>

paper-api/src/main/java/org/bukkit/block/BlockState.java

@@ -96,6 +96,7 @@ public interface BlockState extends Metadatable {
      * If the provided Location is null this method does nothing and returns
      * null.
      *
+     * @param loc the location to copy into
      * @return The Location object provided or null
      */
     Location getLocation(Location loc);