fix: remove spurious parameter docstring after removal

Author: oesteban

sdcflows/workflows/fit/syn.py

@@ -92,9 +92,6 @@ def init_syn_sdc_wf(
         A preprocessed, skull-stripped anatomical (T1w or T2w) image resampled in EPI space.
     anat_mask : :obj:`str`
         Path to the brain mask corresponding to ``anat_ref`` in EPI space.
-    sd_prior : :obj:`str`
-        A template map of areas with strong susceptibility distortions (SD) to regularize
-        the cost function of SyN
 
     Outputs
     -------