Update gmock-spec-builders_test.cc

master branch changed to main in link

googlemock/test/gmock-spec-builders_test.cc

@@ -2059,7 +2059,7 @@ class GMockVerboseFlagTest : public VerboseFlagPreservingFixture {
         "call should not happen.  Do not suppress it by blindly adding "
         "an EXPECT_CALL() if you don't mean to enforce the call.  "
         "See "
-        "https://github.com/google/googletest/blob/master/docs/"
+        "https://github.com/google/googletest/blob/main/docs/"
         "gmock_cook_book.md#"
         "knowing-when-to-expect for details.";