fix typo in libFuzzer documentation

Change-Id: I2076b1659198a70dd2e0ceec7cad34d61727f446
Reviewed-on: https://chromium-review.googlesource.com/963789Reviewed-by: Abhishek Arya <inferno@chromium.org>
Commit-Queue: Abhishek Arya <inferno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543277}

testing/libfuzzer/getting_started.md

@@ -54,7 +54,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
 }
 ```
 
-*Note*: You should create the fuzzer file `<my_fuzzer>.cc next to the code that is being
+*Note*: You should create the fuzzer file `<my_fuzzer>.cc` next to the code that is being
 tested and in the same directory as your other unit tests. Please do not use
 `testing/libfuzzer/fuzzers` directory, this was a directory used for initial sample fuzzers and
 is no longer recommended for any new fuzzers.