Currently, the "exported" logic is used both for expanding wildcard and for knowing if we should check an object for breaking changes. This is not ideal: our "exported" logic is actually only meant for wildcard expansion. See mkdocstrings/python#39 (comment) for context.

Tasks:

• Rename "exported" to "wildcard exposed" or similar
• Fix the "exposed" logic to exclude private members (starting with _) when __all__ is undefined
• Stop making an explicit vs. implicit distinction
• Use new logic in Object.is_public
• Use is_public in API checker instead of "exported" logic