[Fix] Absolut field access

In !319 (merged) we started to make sure that the Field.Access keeps the property is_absolut_access even when sympys simplifications or substitutions kick in. However, there were a few parts missed which are added in this MR

pystencils/field.py

@@ -655,7 +655,7 @@ class Field:
             if len(idx) == 1 and isinstance(idx[0], str):
                 dtype = BasicType(self.field.dtype.numpy_dtype[idx[0]])
                 return Field.Access(self.field, self._offsets, idx,
-                                    is_absolute_access=self.is_absolute_access,  dtype=dtype)
+                                    is_absolute_access=self.is_absolute_access, dtype=dtype)
             else:
                 return Field.Access(self.field, self._offsets, idx,
                                     is_absolute_access=self.is_absolute_access, dtype=self.dtype)