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/neteq/expand.h b/modules/audio_coding/neteq/expand.h
index 35dee65..2d22b11 100644
--- a/modules/audio_coding/neteq/expand.h
+++ b/modules/audio_coding/neteq/expand.h
@@ -45,7 +45,7 @@
   virtual void Reset();
 
   // The main method to produce concealment data. The data is appended to the
-  // end of |output|.
+  // end of `output`.
   virtual int Process(AudioMultiVector* output);
 
   // Prepare the object to do extra expansion during normal operation following
@@ -56,7 +56,7 @@
   // a period of expands.
   virtual void SetParametersForMergeAfterExpand();
 
-  // Returns the mute factor for |channel|.
+  // Returns the mute factor for `channel`.
   int16_t MuteFactor(size_t channel) const {
     RTC_DCHECK_LT(channel, num_channels_);
     return channel_parameters_[channel].mute_factor;
@@ -81,7 +81,7 @@
 
   bool TooManyExpands();
 
-  // Analyzes the signal history in |sync_buffer_|, and set up all parameters
+  // Analyzes the signal history in `sync_buffer_`, and set up all parameters
   // necessary to produce concealment data.
   void AnalyzeSignal(int16_t* random_vector);
 
@@ -115,9 +115,9 @@
     int mute_slope; /* Q20 */
   };
 
-  // Calculate the auto-correlation of |input|, with length |input_length|
+  // Calculate the auto-correlation of `input`, with length `input_length`
   // samples. The correlation is calculated from a downsampled version of
-  // |input|, and is written to |output|.
+  // `input`, and is written to `output`.
   void Correlation(const int16_t* input,
                    size_t input_length,
                    int16_t* output) const;