fix: align parameters in bids_batch_process for improved readability

Author: FabrizioMusacchio

docs/source/usage_batch_conversion.rst

@@ -330,17 +330,15 @@ record, and the supplied ``processing_options``.
            "details": f"{projection} projection along Z; {z_slices} slices -> 1 slice"}
 
    result = om.bids_batch_process(
-       project_root="my_project",
-       subject_prefix="ID",
-       tag_folder_levels=[("TP",)],
-       image_patterns=("*.ome.tif", "*.tif"),
-       output_folder_name="omio_z_projection",
-       output_suffix="_z_projected",
-       process_func=z_projection_process,
-       processing_options={
-           "projection": "max"},
-       save_options={
-           "overwrite": False})
+       project_root        = "my_project",
+       subject_prefix      = "ID",
+       tag_folder_levels   = [("TP",)],
+       image_patterns      = ("*.ome.tif", "*.tif"),
+       output_folder_name  = "omio_z_projection",
+       output_suffix       = "_z_projected",
+       process_func        = z_projection_process,
+       processing_options  = {"projection": "max"},
+       save_options        = {"overwrite": False})
 
 The custom processing callable should return either ``(image, metadata)`` or
 ``(image, metadata, info)``. The optional ``info`` dictionary can add compact