suppress warnings about bad @author tags when author info is not generated.

The JDK API documentation has lots of instances of "bad" @author tags, in that they appear on a member declaration and not on a top-level declaration.

These bad tags can trigger warnings.

Rather than suggesting to remove some or all of these "bad" tags, a different solution would be to suppress the check/warning if author info is not enabled in the doclet (i.e. the `-author` option.)