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

Bug: webrtc:12338
Change-Id: I02613d9fca45d00e2477f334b7a0416e7912e26b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227037
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34621}
diff --git a/modules/audio_coding/acm2/call_statistics.h b/modules/audio_coding/acm2/call_statistics.h
index 5d94ac4..a2db2a29 100644
--- a/modules/audio_coding/acm2/call_statistics.h
+++ b/modules/audio_coding/acm2/call_statistics.h
@@ -36,8 +36,8 @@
   CallStatistics() {}
   ~CallStatistics() {}
 
-  // Call this method to indicate that NetEq engaged in decoding. |speech_type|
-  // is the audio-type according to NetEq, and |muted| indicates if the decoded
+  // Call this method to indicate that NetEq engaged in decoding. `speech_type`
+  // is the audio-type according to NetEq, and `muted` indicates if the decoded
   // frame was produced in muted state.
   void DecodedByNetEq(AudioFrame::SpeechType speech_type, bool muted);