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/buffer_queue.h b/rtc_base/buffer_queue.h
index 09c6c4f..ee435f4 100644
--- a/rtc_base/buffer_queue.h
+++ b/rtc_base/buffer_queue.h
@@ -33,7 +33,7 @@
   // Return number of queued buffers.
   size_t size() const;
 
-  // Clear the BufferQueue by moving all Buffers from |queue_| to |free_list_|.
+  // Clear the BufferQueue by moving all Buffers from `queue_` to `free_list_`.
   void Clear();
 
   // ReadFront will only read one buffer at a time and will truncate buffers