apply 'black' coding style (stricter subset of PEP8)

examples/MCMC_examples/fully_coherent_search_using_MCMC.py

examples/MCMC_examples/semi_coherent_search_using_MCMC.py

...les/followup_examples/semi_coherent_directed_follow_up.py

examples/glitch_examples/make_simulated_data.py

...oherent_glitch_robust_directed_MCMC_search_on_1_glitch.py

...oherent_glitch_robust_directed_grid_search_on_1_glitch.py

...tch_examples/standard_directed_MCMC_search_on_1_glitch.py

examples/grid_examples/grid_F0F1F2.py

examples/grid_examples/grided_frequency_search.py

examples/other_examples/sliding_window.py

examples/other_examples/twoF_cumulative.py

examples/other_examples/using_initialisation.py

examples/transient_examples/long_transient_search_MCMC.py

...ent_examples/long_transient_search_make_simulated_data.py

examples/transient_examples/short_transient_search_MCMC.py

...ples/transient_examples/short_transient_search_gridded.py

...nt_examples/short_transient_search_make_simulated_data.py

pyfstat/__init__.py

pyfstat/core.py

pyfstat/grid_based_searches.py