fix typo (#2820)

Author: sneaxiy

go/codegen/experimental/codegen_test.go

@@ -43,6 +43,6 @@ func TestExperimentalXGBCodegen(t *testing.T) {
 	if err != nil {
 		t.Errorf("error %s", err)
 	}
-	expected := `feature_column_map = {"featuren_columns": [fc.NumericColumn(fd.FieldDesc(name="petal_length", dtype=fd.DataType.FLOAT32, delimiter="", format="", shape=[1], is_sparse=False, vocabulary=[]))]}`
+	expected := `feature_column_map = {"feature_columns": [fc.NumericColumn(fd.FieldDesc(name="petal_length", dtype=fd.DataType.FLOAT32, delimiter="", format="", shape=[1], is_sparse=False, vocabulary=[]))]}`
 	a.True(strings.Contains(coulerCode, expected))
 }

go/codegen/experimental/xgboost.go

@@ -116,7 +116,7 @@ func XGBoostGenerateTrain(trainStmt *ir.TrainStmt, stepIndex int, session *pb.Se
 	return program.String(), nil
 }
 
-var xgbTrainTemplate = `
+const xgbTrainTemplate = `
 def step_entry_{{.StepIndex}}():
     import json
     import tempfile
@@ -141,7 +141,7 @@ def step_entry_{{.StepIndex}}():
     conn = runtime.db.connect_with_data_source(ds)
 
     {{ if .FeatureColumnCode }}
-    feature_column_map = {"featuren_columns": [{{.FeatureColumnCode}}]}
+    feature_column_map = {"feature_columns": [{{.FeatureColumnCode}}]}
     {{ else }}
     feature_column_map = None
     {{ end }}