BF: Use deprecate_with_doc as decorator

Author: effigies

nibabel/loadsave.py

@@ -129,8 +129,8 @@ def save(img, filename):
     converted.to_filename(filename)
 
 
-np.deprecate_with_doc('Please use ``img.dataobj.get_unscaled()`` '
-                      'instead')
+@np.deprecate_with_doc('Please use ``img.dataobj.get_unscaled()`` '
+                       'instead')
 def read_img_data(img, prefer='scaled'):
     """ Read data from image associated with files