[flang][NFC] Update #include and comment.

Differential Revision: https://reviews.llvm.org/D95828

GitOrigin-RevId: af43440bd2f49f9cc548099d35e42734f03735ef
diff --git a/include/flang/Optimizer/Dialect/FIRAttr.h b/include/flang/Optimizer/Dialect/FIRAttr.h
index e000816..e7075f3 100644
--- a/include/flang/Optimizer/Dialect/FIRAttr.h
+++ b/include/flang/Optimizer/Dialect/FIRAttr.h
@@ -5,11 +5,15 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
+//
+// Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/
+//
+//===----------------------------------------------------------------------===//
 
 #ifndef OPTIMIZER_DIALECT_FIRATTR_H
 #define OPTIMIZER_DIALECT_FIRATTR_H
 
-#include "mlir/IR/Attributes.h"
+#include "mlir/IR/BuiltinAttributes.h"
 
 namespace mlir {
 class DialectAsmParser;