After adding a warning for `{@link}` tags that refer to private/protected types, we see these warnings when building javadoc.

```
src/java.base/share/classes/java/util/concurrent/ForkJoinTask.java:134: warning: reference to non-visible type: getException(boolean) (use -protected or -private options to document non-public types)
 * true if the task was cancelled (in which case {@link #getException}
                                                 ^
src/java.base/share/classes/java/util/concurrent/ForkJoinTask.java:137: warning: reference to non-visible type: getException(boolean) (use -protected or -private options to document non-public types)
 * cancelled or encountered an exception, in which case {@link
                                                        ^
src/java.base/share/classes/javax/crypto/KEM.java:711: warning: reference to non-visible type: KEM.Encapsulated.params (use -protected or -private options to document non-public types)
     * {@link Encapsulated#params} field inside the encapsulation output.
       ^
src/java.base/share/classes/java/lang/invoke/MethodHandles.java:4893: warning: reference to non-visible type: primitiveZero(Wrapper) (use -protected or -private options to document non-public types)
     * @see MethodHandles#primitiveZero
       ^
src/java.base/share/classes/java/lang/invoke/MethodHandles.java:2824: warning: reference to non-visible type: Module.reads (use -protected or -private options to document non-public types)
         * {@linkplain Module#reads reads} {@code M0} and the type is
               ^
src/java.base/share/classes/java/lang/invoke/MethodHandles.java:2827: warning: reference to non-visible type: Module.reads (use -protected or -private options to document non-public types)
         * {@linkplain Module#reads reads} {@code M1} and the type is
               ^
src/java.base/share/classes/java/lang/module/ModuleDescriptor.java:2023: warning: reference to non-visible type: ModuleDescriptor.Provides.providers (use -protected or -private options to document non-public types)
         * each {@link Provides#providers provider} (or provider factory) is
                ^

src/java.base/share/classes/java/net/Socket.java:682: warning: reference to non-visible type: isBound(int) (use -protected or -private options to document non-public types)
     * @see #isBound
       ^
src/java.base/share/classes/java/net/Socket.java:1615: warning: reference to non-visible type: isClosed(int) (use -protected or -private options to document non-public types)
     * @see #isClosed
       ^
src/java.base/share/classes/java/net/Socket.java:1645: warning: reference to non-visible type: isInputShutdown(int) (use -protected or -private options to document non-public types)
     * @see #isInputShutdown
       ^
src/java.base/share/classes/java/net/Socket.java:1675: warning: reference to non-visible type: isOutputShutdown(int) (use -protected or -private options to document non-public types)
     * @see #isOutputShutdown
       ^

src/java.base/share/classes/java/lang/Thread.java:1563: warning: reference to non-visible type: interrupted (use -protected or -private options to document non-public types)
     * will report it via {@link #interrupted} and {@link #isInterrupted()}.
                          ^

src/java.base/share/classes/java/lang/invoke/MethodType.java:1335: warning: reference to non-visible type: MethodType.readResolve() (use -protected or -private options to document non-public types)
     * {@link #readResolve readResolve}.
       ^
src/java.base/share/classes/java/lang/invoke/MethodType.java:1340: warning: reference to non-visible type: MethodType.readResolve() (use -protected or -private options to document non-public types)
     * @see #readResolve
       ^
src/java.base/share/classes/java/lang/invoke/MethodType.java:1341: warning: reference to non-visible type: MethodType.writeObject(ObjectOutputStream) (use -protected or -private options to document non-public types)
     * @see #writeObject
       ^
```