Apply suggestions from code review

Co-authored-by: Chris Markiewicz <[email protected]>

Author: tsalo

fmriprep/interfaces/multiecho.py

@@ -69,7 +69,7 @@ class T2SMapInputSpec(CommandLineInputSpec):
         ),
     )
     n_exclude = traits.Int(
-        argstr='--exclude %s',
+        argstr='--exclude 0:%d',
         position=5,
         desc='Number of volumes from the beginning of the run to exclude from T2*/S0 estimation.',
     )
@@ -108,9 +108,6 @@ class T2SMap(CommandLine):
     def _format_arg(self, name, trait_spec, value):
         if name == 'echo_times':
             value = [te * 1000 for te in value]
-        if name == 'n_exclude':
-            # Convert to a range
-            value = f'0:{value}'
         return super()._format_arg(name, trait_spec, value)
 
     def _list_outputs(self):