Use backticks not vertical bars to denote variables in comments for /api

Bug: webrtc:12338
Change-Id: Ib97b2c3d64dbd895f261ffa76a2e885bd934a87f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226940
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34554}
diff --git a/api/test/create_time_controller.h b/api/test/create_time_controller.h
index 1b6896f..e7bc9cb 100644
--- a/api/test/create_time_controller.h
+++ b/api/test/create_time_controller.h
@@ -17,7 +17,7 @@
 
 namespace webrtc {
 
-// Creates a time coltroller that wraps |alarm|.
+// Creates a time coltroller that wraps `alarm`.
 std::unique_ptr<TimeController> CreateTimeController(
     ControlledAlarmClock* alarm);