Fixed a plethora of codestyle issues

eco-api/src/main/java/com/willfp/eco/core/PluginProps.java

@@ -221,7 +221,7 @@ public final class PluginProps {
 
     /**
      * Create new props from known values.
-     *
+     * <p>
      * Marked as internal as this method will break whenever the properties themselves
      * are updated (e.g. if a new property is added) - so to prevent any potential
      * backwards-compatibility bugs, this method cannot be invoked outside eco itself.

eco-api/src/main/java/com/willfp/eco/core/data/keys/PersistentDataKey.java

@@ -134,7 +134,7 @@ public final class PersistentDataKey<T> {
         if (this == o) {
             return true;
         }
-        if (!(o instanceof PersistentDataKey that)) {
+        if (!(o instanceof PersistentDataKey<?> that)) {
             return false;
         }
         return Objects.equals(this.getKey(), that.getKey());

eco-api/src/main/java/com/willfp/eco/core/data/keys/PersistentDataKeyType.java

@@ -99,7 +99,7 @@ public final class PersistentDataKeyType<T> {
         if (this == that) {
             return true;
         }
-        if (!(that instanceof PersistentDataKeyType type)) {
+        if (!(that instanceof PersistentDataKeyType<?> type)) {
             return false;
         }
         return Objects.equals(this.name, type.name);

eco-api/src/main/java/com/willfp/eco/util/DurabilityUtils.java

@@ -16,6 +16,8 @@ import org.jetbrains.annotations.NotNull;
 /**
  * Utilities / API methods for item durability.
  */
+// Have to suppress casts to ItemMeta because the methods don't exist for some older versions that eco supports.
+@SuppressWarnings("RedundantCast")
 public final class DurabilityUtils {
     /**
      * Damage an item in a player's inventory.

eco-api/src/main/java/com/willfp/eco/util/StringUtils.java

@@ -579,7 +579,7 @@ public final class StringUtils {
      *
      * @param lookup The lookup string.
      * @return An array of tokens to be processed.
-     * @author Shawn (https://stackoverflow.com/questions/70606170/split-a-list-on-spaces-and-group-quoted-characters/70606653#70606653)
+     * @author Shawn (<a href="https://stackoverflow.com/questions/70606170/split-a-list-on-spaces-and-group-quoted-characters/70606653#70606653">...</a>)
      */
     @NotNull
     public static String[] parseTokens(@NotNull final String lookup) {

eco-api/src/main/kotlin/com/willfp/eco/core/gui/GUIHelpers.kt

@@ -83,7 +83,6 @@ fun SlotBuilder.setCaptiveFilter(test: (Player, Menu, ItemStack?) -> Boolean): S
  * @deprecated Use SlotUpdater instead.
  */
 @Deprecated("Use SlotUpdater instead")
-@Suppress("DEPRECATION")
 fun SlotBuilder.setModifier(action: (Player, Menu, item: ItemStack) -> Unit): SlotBuilder =
     this.setUpdater { a, b, c -> c.apply { action(a, b, c) } }