Fix part of #4374: Add docstring to file core.storage.job.gae_models.py (#4705)
Fix part of #4374: Add docstring to file core.storage.job.gae_models.py (#4705)

* Added missing docstrings in file: core/storage/job/gae_models.py

* Added missing docstrings in file: core/storage/job/gae_models.py and corrected formatting errors.

* Add docstring at line 91 in file core.storage.job.gae_models, all tests passed.

* Indented at line 96.

* Changed the description to what was was suggested by @seanlip.

* Changed description to 'Whether the job's status_code is..

oppia/oppia,brianrodri/oppia,souravbadami/oppia,kevinlee12/oppia,AllanYangZhou/oppia,oppia/oppia,kevinlee12/oppia,AllanYangZhou/oppia,souravbadami/oppia,prasanna08/oppia,oppia/oppia,prasanna08/oppia,oppia/oppia,prasanna08/oppia,brianrodri/oppia,souravbadami/oppia,brianrodri/oppia,prasanna08/oppia,kevinlee12/oppia,souravbadami/oppia,AllanYangZhou/oppia,souravbadami/oppia,oppia/oppia,kevinlee12/oppia,brianrodri/oppia,AllanYangZhou/oppia,prasanna08/oppia,kevinlee12/oppia,brianrodri/oppia