doc: escape asterisk in cctest gtest-filter

RaisinTen · danielleadams · commit dcb27600da7b · 2020-11-10T11:40:59.000-05:00
PR-URL: #36034 Reviewed-By: Rich Trott <rtrott@gmail.com> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
diff --git a/doc/guides/writing-tests.md b/doc/guides/writing-tests.md
@@ -418,7 +418,7 @@ $ make cctest GTEST_FILTER=EnvironmentTest.AtExitWithArgument
 `cctest` can also be run directly which can be useful when debugging:
 
 ```console
-$ out/Release/cctest --gtest_filter=EnvironmentTest.AtExit*
+$ out/Release/cctest --gtest_filter=EnvironmentTest.AtExit\*
 ```
 
 ### Node.js test fixture
