emphasis on "higher return values are better..." (#6909)

Yoav Ram · agramfort · commit 6301b1f72753 · 2016-06-19T14:46:13.000+02:00
diff --git a/doc/modules/model_evaluation.rst b/doc/modules/model_evaluation.rst
@@ -48,8 +48,8 @@ Common cases: predefined values
 
 For the most common use cases, you can designate a scorer object with the
 ``scoring`` parameter; the table below shows all possible values.
-All scorer objects follow the convention that higher return values are better
-than lower return values.  Thus the returns from mean_absolute_error
+All scorer objects follow the convention that **higher return values are better
+than lower return values**.  Thus the returns from mean_absolute_error
 and mean_squared_error, which measure the distance between the model
 and the data, are negated.
 
