pw_unit_test: Include the right gmock header

Bug: 309665550

Change-Id: Ia258bd4d640a74befda5b66cf6ec73190ef2825f
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/180030
Pigweed-Auto-Submit: Carlos Chinchilla <cachinchilla@google.com>
Reviewed-by: Ted Pudlik <tpudlik@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed-service-accounts.iam.gserviceaccount.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/pw_unit_test/public/pw_unit_test/googletest_test_matchers.h b/pw_unit_test/public/pw_unit_test/googletest_test_matchers.h
index dfc1be4..e7965aa 100644
--- a/pw_unit_test/public/pw_unit_test/googletest_test_matchers.h
+++ b/pw_unit_test/public/pw_unit_test/googletest_test_matchers.h
@@ -16,7 +16,7 @@
 #include <type_traits>
 #include <utility>
 
-#include "gmock/gmock.h"
+#include "gmock/gmock-matchers.h"
 #include "gtest/gtest.h"
 #include "pw_result/result.h"
 #include "pw_status/status.h"
@@ -253,4 +253,4 @@
 #define UNIQUE_IDENTIFIER_EXPANDED_DETAIL(line) \
   _assert_ok_and_assign_unique_name_##line
 
-}  // namespace pw::unit_test
\ No newline at end of file
+}  // namespace pw::unit_test