Previously, RestDocumentationContextPlaceholderResolver could be
subclassed, but it didn’t provide access to its state (the
RestDocumentationContext).
This commit opens up RestDocumentationContextPlaceholderResolver by
adding a getter method for its RestDocumentationContext. It also makes
the kebab-base and snake_case conversion methods protected (rather than
private) so that they can be used by subclasses.
See gh-116
5dc28b9bb0