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

Bug: webrtc:12338
Change-Id: Ib97b2c3d64dbd895f261ffa76a2e885bd934a87f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226940
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34554}
diff --git a/api/rtp_receiver_interface.h b/api/rtp_receiver_interface.h
index 327c9f2..e4ec9b5 100644
--- a/api/rtp_receiver_interface.h
+++ b/api/rtp_receiver_interface.h
@@ -54,7 +54,7 @@
   // TODO(https://bugs.webrtc.org/907849) remove default implementation
   virtual rtc::scoped_refptr<DtlsTransportInterface> dtls_transport() const;
 
-  // The list of streams that |track| is associated with. This is the same as
+  // The list of streams that `track` is associated with. This is the same as
   // the [[AssociatedRemoteMediaStreams]] internal slot in the spec.
   // https://w3c.github.io/webrtc-pc/#dfn-associatedremotemediastreams
   // TODO(hbos): Make pure virtual as soon as Chromium's mock implements this.
@@ -84,8 +84,8 @@
   virtual void SetObserver(RtpReceiverObserverInterface* observer) = 0;
 
   // Sets the jitter buffer minimum delay until media playout. Actual observed
-  // delay may differ depending on the congestion control. |delay_seconds| is a
-  // positive value including 0.0 measured in seconds. |nullopt| means default
+  // delay may differ depending on the congestion control. `delay_seconds` is a
+  // positive value including 0.0 measured in seconds. `nullopt` means default
   // value must be used.
   virtual void SetJitterBufferMinimumDelay(
       absl::optional<double> delay_seconds) = 0;