This is loosely related to Highcharts, but they have a great documentation at http://api.highcharts.com/highcharts and I'd like to know how it is made.
Its actually not generated from source; instead we have database model where we can express inheritance/overrides/deprecation/version/return types/... and other meta-data for each property. The database is currently a mongodb instance but could really be any type of database.
On top of the database there is a rest api that the webpage is using to query for more options (when you click "expand" on a node). The server is implemented as a java webapp using the spring-framework and the webpage is implemented using jquery+jquery-ui.