TimezoneTransition is missing from the API documentation

[tobinus]

Overview Description

The TimezoneTransition class in babel.dates is mentioned in the API description of get_next_timezone_transition, but it is never said anywhere what attributes this class has.

The get_next_timezone_transition could specify its return type in its doc text with a reStructuredText markup (instead of only mentioning this in the description), and the TimezoneTransition class should be included in the docs/api/dates.rst document.

Steps to Reproduce

1. Navigate to http://babel.pocoo.org/en/latest/api/dates.html#babel.dates.get_next_timezone_transition
2. Try looking for a description of what properties TimezoneTransition has

Actual Results

The properties of TimezoneTransition are not described anywhere in the generated HTML documentation.

Expected Results

The properties of TimezoneTransition are described right next to get_next_timezone_transition.