Fixed clang tidy

verible/verilog/formatting/formatter_issue_regression_test.cc

diff --git a/verible/verilog/formatting/formatter_issue_regression_test.cc b/verible/verilog/formatting/formatter_issue_regression_test.cc
index 3775053..4434bab 100644
--- a/verible/verilog/formatting/formatter_issue_regression_test.cc
+++ b/verible/verilog/formatting/formatter_issue_regression_test.cc
@@ -20,6 +20,7 @@
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
+#include "verible/common/formatting/basic-format-style.h"
 #include "verible/common/util/logging.h"
 #include "verible/verilog/formatting/format-style.h"
 #include "verible/verilog/formatting/formatter-test-utils.h"