fix: single file doctest

Author: mgxd

nipype/interfaces/dcm2nii.py

@@ -216,9 +216,10 @@ class Dcm2niix(CommandLine):
     >>> converter = Dcm2niix()
     >>> converter.inputs.source_names = ['functional_1.dcm', 'functional_2.dcm']
     >>> converter.inputs.compress = 'i'
+    >>> converter.inputs.single_file = True
     >>> converter.inputs.output_dir = '.'
     >>> converter.cmdline
-    'dcm2niix -b y -z i -m n -f %t%p -o . -s n -v n functional_1.dcm'
+    'dcm2niix -b y -z i -m n -f %t%p -o . -s y -v n functional_1.dcm'
     """
 
     input_spec = Dcm2niixInputSpec