Fix Types of Sample Programs Method

[jrg94]

This is no longer valid:

    def sample_programs(self) -> List[SampleProgram]:
        """
        Retrieves the list of sample programs associated with this language.

        Assuming you have a LanguageCollection object called language, 
        here's how you would use this method::

            programs: List[SampleProgram] = language.sample_programs()

        :return: the list of sample programs
        """
        return self._sample_programs

Sample programs is a dict.