Remove now-unused keyword argument

When we switched from just printing the error to raising it as an
exception, we accidentally left the `file` argument in.
It's not needed and not accepted by ValueError.

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Bugfix: Remove unused keyword argument from exception ([#755](https://github.com/mozilla/glean_parser/pull/755))
+
 ## 15.0.1
 
 - Rust codegen: use correctly named parameter for events without extras ([#750](https://github.com/mozilla/glean_parser/pull/750))

glean_parser/translate.py

@@ -11,7 +11,6 @@
 from pathlib import Path
 import os
 import shutil
-import sys
 import tempfile
 from typing import Any, Callable, Dict, Iterable, List, Optional
 
@@ -98,7 +97,6 @@ def transform_metrics(objects):
             raise ValueError(
                 f"No `counter` named {denominator_name} found to be used as"
                 "denominator for {numerators}",
-                file=sys.stderr,
             )
         counters[denominator_name].__class__ = metrics.Denominator
         counters[denominator_name].type = "denominator"