Docstrings missing type or annotation

[jhkennedy]

When we build the API reference for hyp3-docs, mkdocstrings complains about some of the asf_tools docstrings:

- [ ] WARNING  -  griffe: asf_tools/composite.py:106: No type or annotation for returned value 'upper_left'
- [ ] WARNING  -  griffe: asf_tools/composite.py:107: No type or annotation for returned value 'upper_right'
- [ ] WARNING  -  griffe: asf_tools/composite.py:108: No type or annotation for returned value 'geotransform'
- [ ] WARNING  -  griffe: asf_tools/composite.py:232: No type or annotation for returned value 'out_raster'
- [ ] WARNING  -  griffe: asf_tools/composite.py:233: No type or annotation for returned value 'out_counts_raster'
- [ ] WARNING  -  griffe: asf_tools/composite.py:198: No type or annotation for parameter 'dtype'
- [ ] WARNING  -  griffe: asf_tools/composite.py:199: No type or annotation for parameter 'nodata_value'
- [ ] WARNING  -  griffe: asf_tools/composite.py:202: No type or annotation for returned value 'file_name'
- [ ] WARNING  -  griffe: asf_tools/hand/calculate.py:81: No type or annotation for parameter 'dem_array'
- [ ] WARNING  -  griffe: asf_tools/hand/calculate.py:84: No type or annotation for parameter 'basin_mask'
- [ ] WARNING  -  griffe: asf_tools/util.py:10: No type or annotation for parameter '**options'