This enum, which can be found in Xamarin's iOS and Mac products use a custom encoding
scheme which resulted in invalid values being shown when processed with mdoc. This patch
adds a special case to watch for this particular enumeration value, and decodes the data
correctly.
Additionally, the code that formats the values for flags enumerations was refactored. Future extensibility of this feature can now be done by simply implementing a new `FlagsFormatter`, and applying the proper logic in the `MakeAttributesValueString` function.
