Add missing newline

Bug: None
Change-Id: Ic2d7ae4c45a55b708b8ff1b63d56cb845985ecc3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/375200
Commit-Queue: Fanny Linderborg <linderborg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43795}

g3doc/style-guide.md

@@ -111,6 +111,7 @@ inline std::pony PonyPlz(const std::pony_spec& ps) {
 }
 ```
 or wrap the test with
+
 ```cpp
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"