The `style(Object)` method in DefaultValueStyler delegates to several
internal methods. Prior to this commit those methods were private,
which prevented users from extending DefaultValueStyler without
rewriting most of the functionality.
This commit addresses this by making those methods protected so that
DefaultValueStyler can be extended. In addition, this commit introduces
protected methods for styling null, strings, classes, methods, and
objects that are not covered by any of the other style*() methods.
Closes gh-29380
388f7bffcb