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

Bug: webrtc:12338
Change-Id: I72fcb505a92f03b2ace7160ee33d555a977eddfd
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226955
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34587}
diff --git a/rtc_base/task_queue_for_test.h b/rtc_base/task_queue_for_test.h
index dd5679b..97ca254 100644
--- a/rtc_base/task_queue_for_test.h
+++ b/rtc_base/task_queue_for_test.h
@@ -49,7 +49,7 @@
   // a task executes on the task queue.
   // This variant is specifically for posting custom QueuedTask derived
   // implementations that tests do not want to pass ownership of over to the
-  // task queue (i.e. the Run() method always returns |false|.).
+  // task queue (i.e. the Run() method always returns `false`.).
   template <class Closure>
   void SendTask(Closure* task) {
     RTC_CHECK(!IsCurrent());