After adding a warning for `{@link}` tags that refer to private/protected types, we see these warnings when building javadoc.
```
src/jdk.incubator.vector/share/classes/jdk/incubator/vector/Vector.java:163: warning: reference to non-visible type: VectorShape.largestShapeFor(Class) (use -protected or -private options to document non-public types)
* {@linkplain VectorShape#largestShapeFor(Class) largest
^
```
```
src/jdk.incubator.vector/share/classes/jdk/incubator/vector/Vector.java:163: warning: reference to non-visible type: VectorShape.largestShapeFor(Class) (use -protected or -private options to document non-public types)
* {@linkplain VectorShape#largestShapeFor(Class) largest
^
```