Update a docstring in readinput.py
Update a docstring in readinput.py

Removed a reference to a non-existent function `get_exposure_lazy`.

Former-commit-id: 54bc7284e98fd43745c9bc3eb242042d18633b9e [formerly b85cb50c6f57dc9066ac8824ea93e0b58fce5b70] [formerly b85cb50c6f57dc9066ac8824ea93e0b58fce5b70 [formerly 573f7dc7f73f5279f5c2c28f5220d14573a994e0]]
Former-commit-id: c3d1a9e21ff22d48fe69f06cfb6aa915b2f73f66
Former-commit-id: 63ab4ecc08a146582c517687f41df9c2bd79f230
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine