4.x: Fix Javadoc warnings

[dkropachev]

Warning:  Javadoc Warnings
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/Recycler.java:27: error: package org.jetbrains.annotations does not exist
Warning:  import org.jetbrains.annotations.VisibleForTesting;
Warning:  ^
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/concurrent/GlobalEventExecutor.java:24: error: package org.jetbrains.annotations.Async does not exist
Warning:  import org.jetbrains.annotations.Async.Schedule;
Warning:  ^
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/concurrent/AbstractEventExecutor.java:22: error: package org.jetbrains.annotations.Async does not exist
Warning:  import org.jetbrains.annotations.Async.Execute;
Warning:  ^
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/concurrent/SingleThreadEventExecutor.java:24: error: package org.jetbrains.annotations.Async does not exist
Warning:  import org.jetbrains.annotations.Async.Schedule;
Warning:  ^
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/internal/BoundedInputStream.java:18: error: package org.jetbrains.annotations does not exist
Warning:  import org.jetbrains.annotations.NotNull;
Warning:  ^
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/Recycler.java:211: error: cannot find symbol
Warning:  @VisibleForTesting
Warning:  ^
Warning:  symbol:   class VisibleForTesting
Warning:  location: class Recycler<T>
Warning:  where T is a type-variable:
Warning:  T extends Object declared in class Recycler
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/concurrent/GlobalEventExecutor.java:224: error: cannot find symbol
Warning:  private void execute0(@Schedule Runnable task) {
Warning:  ^
Warning:  symbol:   class Schedule
Warning:  location: class GlobalEventExecutor
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/concurrent/AbstractEventExecutor.java:172: error: cannot find symbol
Warning:  protected static void runTask(@Execute Runnable task) {
Warning:  ^
Warning:  symbol:   class Execute
Warning:  location: class AbstractEventExecutor
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/concurrent/SingleThreadEventExecutor.java:825: error: cannot find symbol
Warning:  private void execute0(@Schedule Runnable task) {
Warning:  ^
Warning:  symbol:   class Schedule
Warning:  location: class SingleThreadEventExecutor
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/concurrent/SingleThreadEventExecutor.java:830: error: cannot find symbol
Warning:  private void lazyExecute0(@Schedule Runnable task) {
Warning:  ^
Warning:  symbol:   class Schedule
Warning:  location: class SingleThreadEventExecutor
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/internal/BoundedInputStream.java:29: error: cannot find symbol
Warning:  public BoundedInputStream(@NotNull InputStream in, int maxBytesRead) {
Warning:  ^
Warning:  symbol:   class NotNull
Warning:  location: class BoundedInputStream
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/shaded/netty/util/internal/BoundedInputStream.java:34: error: cannot find symbol
Warning:  public BoundedInputStream(@NotNull InputStream in) {
Warning:  ^
Warning:  symbol:   class NotNull
Warning:  location: class BoundedInputStream
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/api/core/session/Request.java:104: warning: no description for @return
Warning:  * @return
Warning:  ^
Warning:  /home/runner/work/java-driver/java-driver/core-shaded/target/shaded-sources/com/datastax/oss/driver/api/core/data/CqlVector.java:87: warning: no description for @param
Warning:  * @param subtypeCodec
Warning:  ^