Fix outdated target_group naming in error message

The target_groups config has been renamed to static_configs, the error
message for overflow attributes should reflect that.

config/config.go

@@ -728,7 +728,7 @@ func (tg *TargetGroup) UnmarshalYAML(unmarshal func(interface{}) error) error {
 		})
 	}
 	tg.Labels = g.Labels
-	return checkOverflow(g.XXX, "target_group")
+	return checkOverflow(g.XXX, "static_config")
 }
 
 // MarshalYAML implements the yaml.Marshaler interface.

discovery/file/file_test.go

@@ -60,7 +60,7 @@ func testFileSD(t *testing.T, ext string) {
 	}
 	defer newf.Close()
 
-	f, err := os.Open("fixtures/target_groups" + ext)
+	f, err := os.Open("fixtures/valid" + ext)
 	if err != nil {
 		t.Fatal(err)
 	}