[Fixes #640] Support verifying private methods for any_instance
Merge pull request #641 from orend/support_any_instance_private_methods

Support verifying private methods for any_instance
Add changelog entry for #641.

[ci skip]
fix a small typo in changelog
Merge pull request #642 from orend/patch-2

fix a small typo in changelog
match mocks to expectations/core and not exclude yard
`@api private` had no effect here so lets make them `@private`