chore: Update pretty_mapping to use f-strings

Author: effigies

nibabel/volumeutils.py

@@ -338,12 +338,7 @@ def pretty_mapping(
     if getterfunc is None:
         getterfunc = getitem
     mxlen = max(len(str(name)) for name in mapping)
-    fmt = '%%-%ds  : %%s' % mxlen
-    out = []
-    for name in mapping:
-        value = getterfunc(mapping, name)
-        out.append(fmt % (name, value))
-    return '\n'.join(out)
+    return '\n'.join([f'{name:{mxlen}s}  : {getterfunc(mapping, name)}' for name in mapping])
 
 
 def make_dt_codes(codes_seqs: ty.Sequence[ty.Sequence]) -> Recoder: