Fix ValueError message formatting in 'make_xeditable' helper

The existing error message for the 'make_xeditable' helper was split across multiple lines unnecessarily. This commit consolidates the message into fewer lines, improving readability and maintaining the same information.

datatableview/helpers.py

@@ -338,11 +338,8 @@ def make_xeditable(instance=None, extra_attrs=[], *args, **kwargs):  # noqa: C90
         # Legacy syntax
         field_name = field_name[1]
         if isinstance(field_name, (tuple, list)):
-            raise ValueError(
-                "'make_xeditable' helper needs a single-field data column," " not {0!r}".format(
-                    field_name
-                )
-            )
+            msg = f"'make_xeditable' helper needs a single-field data column, not {field_name!r}"
+            raise ValueError(msg)
     attrs["data-name"] = field_name
 
     if isinstance(rich_data, Model):