Cannot generate because `No module named 'openfisca_core.types.data_types'`

[MattiSG]

As seen in this job, after merging https://github.com/openfisca/openfisca-core/pull/1151 and following https://github.com/openfisca/openfisca-core/pull/1145, the documentation build is broken, which means that it is both not up to date and cannot be updated manually.

The error is the following:

Warning, treated as error: autodoc: failed to import module 'data_types.arrays' from module 'openfisca_core.types'; the following exception was raised: No module named 'openfisca_core.types.data_types'

[MattiSG]

@maukoquiroga @benjello you dropped the doc check in Core that prevented this situation in https://github.com/openfisca/openfisca-core/pull/1145, can you please have a look at this and suggest a way out? Thanks :)

[MattiSG]

Fixed via #283