Fix docstring formats (#3196)

.isort.cfg

.pre-commit-config.yaml

docs/make.bat

mmdet/apis/inference.py

mmdet/core/anchor/anchor_generator.py

mmdet/core/anchor/utils.py

mmdet/core/bbox/__init__.py

mmdet/core/bbox/assigners/assign_result.py

mmdet/core/bbox/assigners/base_assigner.py

mmdet/core/bbox/assigners/center_region_assigner.py

mmdet/core/bbox/assigners/point_assigner.py

mmdet/core/bbox/builder.py

mmdet/core/bbox/coder/base_bbox_coder.py

mmdet/core/bbox/coder/delta_xywh_bbox_coder.py

mmdet/core/bbox/coder/legacy_delta_xywh_bbox_coder.py

mmdet/core/bbox/coder/pseudo_bbox_coder.py

mmdet/core/bbox/coder/tblr_bbox_coder.py

mmdet/core/bbox/demodata.py

mmdet/core/bbox/iou_calculators/builder.py

mmdet/core/bbox/iou_calculators/iou2d_calculator.py