Reland "Use backticks not vertical bars to denote variables in comments for /pc"

Original change's description:
> Revert "Use backticks not vertical bars to denote variables in comments for /pc"
>
> This reverts commit 37ee0f5e594dd772ec6d620b5e5ea8a751b684f0.
>
> Reason for revert: Revert in order to be able to revert https://webrtc-review.googlesource.com/c/src/+/225642
>
> Original change's description:
> > Use backticks not vertical bars to denote variables in comments for /pc
> >
> > Bug: webrtc:12338
> > Change-Id: I88cf10afa5fc810b95d2a585ab2e895dcc163b63
> > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226953
> > Reviewed-by: Harald Alvestrand <hta@webrtc.org>
> > Commit-Queue: Artem Titov <titovartem@webrtc.org>
> > Cr-Commit-Position: refs/heads/master@{#34575}
>
> TBR=hta@webrtc.org,titovartem@webrtc.org,webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com
>
> Change-Id: I5eddd3a14e1f664bf831e5c294fbc4de5f6a88af
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: webrtc:12338
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227082
> Reviewed-by: Björn Terelius <terelius@webrtc.org>
> Commit-Queue: Björn Terelius <terelius@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#34577}

Bug: webrtc:12338
Change-Id: I96bd229b73613c162d11d75fa4f5934e1b4295c7
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227087
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34611}

pc/media_session.h

diff --git a/pc/media_session.h b/pc/media_session.h
index d4c8025..bb97f42 100644
--- a/pc/media_session.h
+++ b/pc/media_session.h
@@ -50,7 +50,7 @@
   // Use RIDs and Simulcast Layers to indicate spec-compliant Simulcast.
   std::vector<RidDescription> rids;
   SimulcastLayerList simulcast_layers;
-  // Use |num_sim_layers| to indicate legacy simulcast.
+  // Use `num_sim_layers` to indicate legacy simulcast.
   int num_sim_layers;
 };
 
@@ -84,7 +84,7 @@
   std::vector<webrtc::RtpHeaderExtensionCapability> header_extensions;
 
  private:
-  // Doesn't DCHECK on |type|.
+  // Doesn't DCHECK on `type`.
   void AddSenderInternal(const std::string& track_id,
                          const std::vector<std::string>& stream_ids,
                          const std::vector<RidDescription>& rids,