Fix Checkstyle issues again

proxy/src/main/java/com/velocitypowered/proxy/util/collect/Enum2IntMap.java

@@ -2,6 +2,10 @@ package com.velocitypowered.proxy.util.collect;
 
 import java.util.EnumSet;
 
+/**
+ * An immutable map of {@link Enum} entries to {@code int}s.
+ * @param <E> the enum type
+ */
 public class Enum2IntMap<E extends Enum<E>> {
   private final int[] mappings;
 
@@ -23,6 +27,12 @@ public class Enum2IntMap<E extends Enum<E>> {
       this.populated = EnumSet.noneOf(klazz);
     }
 
+    /**
+     * Adds a mapping to the map.
+     * @param key the key to use
+     * @param value the value to associate with the key
+     * @return {@code this}, for chaining
+     */
     public Builder<E> put(E key, int value) {
       this.mappings[key.ordinal()] = value;
       this.populated.add(key);
@@ -39,6 +49,11 @@ public class Enum2IntMap<E extends Enum<E>> {
       return this;
     }
 
+    /**
+     * Fetches a mapping from the map.
+     * @param key the key to use
+     * @return the value in the map
+     */
     public int get(E key) {
       if (this.populated.contains(key)) {
         return this.mappings[key.ordinal()];
@@ -46,6 +61,10 @@ public class Enum2IntMap<E extends Enum<E>> {
       return this.defaultValue;
     }
 
+    /**
+     * Builds the map.
+     * @return the built map
+     */
     public Enum2IntMap<E> build() {
       for (E unpopulated : EnumSet.complementOf(this.populated)) {
         this.mappings[unpopulated.ordinal()] = this.defaultValue;