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/dtmf_buffer.h b/modules/audio_coding/neteq/dtmf_buffer.h
index 6bf75e1..9209cae 100644
--- a/modules/audio_coding/neteq/dtmf_buffer.h
+++ b/modules/audio_coding/neteq/dtmf_buffer.h
@@ -45,7 +45,7 @@
     kInvalidSampleRate
   };
 
-  // Set up the buffer for use at sample rate |fs_hz|.
+  // Set up the buffer for use at sample rate `fs_hz`.
   explicit DtmfBuffer(int fs_hz);
 
   virtual ~DtmfBuffer();
@@ -53,21 +53,21 @@
   // Flushes the buffer.
   virtual void Flush();
 
-  // Static method to parse 4 bytes from |payload| as a DTMF event (RFC 4733)
-  // and write the parsed information into the struct |event|. Input variable
-  // |rtp_timestamp| is simply copied into the struct.
+  // Static method to parse 4 bytes from `payload` as a DTMF event (RFC 4733)
+  // and write the parsed information into the struct `event`. Input variable
+  // `rtp_timestamp` is simply copied into the struct.
   static int ParseEvent(uint32_t rtp_timestamp,
                         const uint8_t* payload,
                         size_t payload_length_bytes,
                         DtmfEvent* event);
 
-  // Inserts |event| into the buffer. The method looks for a matching event and
+  // Inserts `event` into the buffer. The method looks for a matching event and
   // merges the two if a match is found.
   virtual int InsertEvent(const DtmfEvent& event);
 
-  // Checks if a DTMF event should be played at time |current_timestamp|. If so,
+  // Checks if a DTMF event should be played at time `current_timestamp`. If so,
   // the method returns true; otherwise false. The parameters of the event to
-  // play will be written to |event|.
+  // play will be written to `event`.
   virtual bool GetEvent(uint32_t current_timestamp, DtmfEvent* event);
 
   // Number of events in the buffer.
@@ -87,7 +87,7 @@
   // Compares two events and returns true if they are the same.
   static bool SameEvent(const DtmfEvent& a, const DtmfEvent& b);
 
-  // Merges |event| to the event pointed out by |it|. The method checks that
+  // Merges `event` to the event pointed out by `it`. The method checks that
   // the two events are the same (using the SameEvent method), and merges them
   // if that was the case, returning true. If the events are not the same, false
   // is returned.