add comment (warning about generated files)

R=r
CC=golang-dev
https://golang.org/cl/180108

src/pkg/exp/vector/intvector.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// CAUTION: If this file is not vector.go, it was generated
+// automatically from vector.go - DO NOT EDIT in that case!
+
 package vector
 
 

src/pkg/exp/vector/intvector_test.go

@@ -2,8 +2,10 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package vector
+// CAUTION: If this file is not vector_test.go, it was generated
+// automatically from vector_test.go - DO NOT EDIT in that case!
 
+package vector
 
 import "testing"
 

src/pkg/exp/vector/stringvector.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// CAUTION: If this file is not vector.go, it was generated
+// automatically from vector.go - DO NOT EDIT in that case!
+
 package vector
 
 

src/pkg/exp/vector/stringvector_test.go

@@ -2,8 +2,10 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package vector
+// CAUTION: If this file is not vector_test.go, it was generated
+// automatically from vector_test.go - DO NOT EDIT in that case!
 
+package vector
 
 import "testing"
 

src/pkg/exp/vector/vector.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// CAUTION: If this file is not vector.go, it was generated
+// automatically from vector.go - DO NOT EDIT in that case!
+
 package vector
 
 

src/pkg/exp/vector/vector_test.go

@@ -2,8 +2,10 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package vector
+// CAUTION: If this file is not vector_test.go, it was generated
+// automatically from vector_test.go - DO NOT EDIT in that case!
 
+package vector
 
 import "testing"