Updated comments for metric_specs.output_names to indicate that it is required for multi-output models.

PiperOrigin-RevId: 390480764

Author: mdreves

tensorflow_model_analysis/proto/config.proto

@@ -461,7 +461,7 @@ message MetricsSpec {
   // the model_specs will be assumed else these metrics will only be
   // computed for the model names provided.
   repeated string model_names = 2;
-  // Optional names of outputs the metrics should be calculated for (for
+  // Names of outputs the metrics should be calculated for (required for
   // multi-output models). See comment under the ModelSpec.prediction_key on the
   // difference between output_name and prediction_key.
   repeated string output_names = 3;