http://d-programming-language.org/class.html is quite messed up at the moment. Aside from the code examples, it's _very_ difficult to read any of it, since it's all way too dark. It starts with $(SPEC_S Classes, and its ddoc is clearly messed up. It should be fixed ASAP, since this has a major impact on anyone trying to learn D from the online docs.
https://github.com/D-Programming-Language/d-programming-language.org/pull/33
Technical fixes pull, also contains a fix of this bug: https://github.com/D-Programming-Language/d-programming-language.org/pull/28