Two classes lack class doc blocks

There are two classes in Core that I know of that do not have class doc blocks:

a) core/lib/Drupal/Core/Logger/RfcLogLevel.php -- there is a doc block in the file that precedes the class, but it has a @defgroup in it. So it is not a class doc block.

What needs to happen is to leave a blank line after the current defgroup doc block, and add a new short doc block to the class with a short description and "@ingroup logging_severity_levels" in it.

b) core/modules/views/src/Plugin/views/field/FieldPluginBase.php -- has exactly the same problem. The @ingroup line should say views_field_handlers in this case.

c) There may be some other classes with the same problem. I'm checking on that. I found these due to #2402361: Notice in parser.inc for classes with malformed class doc block in the API module, and due to that bug, currently on api.drupal.org, the API module is getting confused when it parses these files and it's not creating Class pages for either of them, meaning also that links to those classes from other classes and code are not working... On my local machine, I'm currently reparsing the entire Drupal 8 code base to see if this error occurs on any other files.

BETA EVAL: This is a bug because classes are missing documentation, and it's major because all classes are supposed to have documentation, according to the Documentation gate, and these don't.