[ci skip] Add javadocs warnings about unsupported operations (#1250)

* Document possible blank spaces in the command of the CommandExecuteEvent

* Added Javadocs warning about unimplemented methods in Velocity

* Improved KickedFromServerEvent documentation

* Fixed `apiNote` javadoc generation

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -943,7 +943,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
   }
 
   @Override
-  public boolean sendPluginMessage(ChannelIdentifier identifier, byte[] data) {
+  public boolean sendPluginMessage(@NotNull ChannelIdentifier identifier, byte @NotNull [] data) {
     Preconditions.checkNotNull(identifier, "identifier");
     Preconditions.checkNotNull(data, "data");
     PluginMessagePacket message = new PluginMessagePacket(identifier.getId(),
@@ -1099,12 +1099,12 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
   }
 
   @Override
-  public Collection<ResourcePackInfo> getAppliedResourcePacks() {
+  public @NotNull Collection<ResourcePackInfo> getAppliedResourcePacks() {
     return this.resourcePackHandler.getAppliedResourcePacks();
   }
 
   @Override
-  public Collection<ResourcePackInfo> getPendingResourcePacks() {
+  public @NotNull Collection<ResourcePackInfo> getPendingResourcePacks() {
     return this.resourcePackHandler.getPendingResourcePacks();
   }
 

proxy/src/main/java/com/velocitypowered/proxy/connection/player/resourcepack/LegacyResourcePackHandler.java

@@ -34,7 +34,7 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 import org.jetbrains.annotations.NotNull;
 
 /**
- * Legacy (Minecraft <1.17) ResourcePackHandler.
+ * Legacy (Minecraft &lt;1.17) ResourcePackHandler.
  */
 public sealed class LegacyResourcePackHandler extends ResourcePackHandler
         permits Legacy117ResourcePackHandler {

proxy/src/main/java/com/velocitypowered/proxy/connection/player/resourcepack/ResourcePackHandler.java

@@ -117,27 +117,27 @@ public abstract sealed class ResourcePackHandler
 
   /**
    * Processes a client response to a sent resource-pack.
-   * <ul>
    * <p>Cases in which no action will be taken:</p>
+   * <ul>
    *
-   * <br><li><b>DOWNLOADED</b>
+   * <li><b>DOWNLOADED</b>
    * <p>In this case the resource pack is downloaded and will be applied to the client,
    * no action is required in Velocity.</p>
    *
-   * <br><li><b>INVALID_URL</b>
+   * <li><b>INVALID_URL</b>
    * <p>In this case, the client has received a resource pack request
    * and the first check it performs is if the URL is valid, if not,
    * it will return this value</p>
    *
-   * <br><li><b>FAILED_RELOAD</b>
+   * <li><b>FAILED_RELOAD</b>
    * <p>In this case, when trying to reload the client's resources,
    * an error occurred while reloading a resource pack</p>
-   * </ul>
    *
-   * <br><li><b>DECLINED</b>
+   * <li><b>DECLINED</b>
    * <p>Only in modern versions, as the resource pack has already been rejected,
    * there is nothing to do, if the resource pack is required,
    * the client will be kicked out of the server.</p>
+   * </ul>
    *
    * @param bundle the resource pack response bundle
    */

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/PlayPacketQueueHandler.java

@@ -46,7 +46,7 @@ public class PlayPacketQueueHandler extends ChannelDuplexHandler {
   private final Queue<MinecraftPacket> queue = PlatformDependent.newMpscQueue();
 
   /**
-   * Provides registries for client & server bound packets.
+   * Provides registries for client &amp; server bound packets.
    *
    * @param version the protocol version
    */