`CheckExampleAndDefaultValue` signature: It would be best to stay along in lines with the other `Check...` functions in Snow Crash like [`CheckSignature`](https://github.com/apiaryio/snowcrash/blob/master/src/PayloadParser.h#L562) or [`CheckParametersEligibility`](https://github.com/apiaryio/snowcrash/blob/master/src/ResourceParser.h#L402) or [`CheckHeaderDuplicates](https://github.com/apiaryio/snowcrash/blob/master/src/HeaderParser.h#L270) or [`CheckBlueprintName`](https://github.com/apiaryio/snowcrash/blob/master/src/BlueprintParser.h#L90) – 

Keep the signature similar return `void` or `bool` and use `Result` for returning any annotations. You do not really need to return full `ParseSectionResult` since that includes potentially changed position in the source Markdown AST which a check function MUST not alter.