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}
diff --git a/pc/rtc_stats_integrationtest.cc b/pc/rtc_stats_integrationtest.cc
index df7b8a3..afa50d8 100644
--- a/pc/rtc_stats_integrationtest.cc
+++ b/pc/rtc_stats_integrationtest.cc
@@ -192,7 +192,7 @@
     return stats_obtainer->report();
   }
 
-  // |network_thread_| uses |virtual_socket_server_| so they must be
+  // `network_thread_` uses `virtual_socket_server_` so they must be
   // constructed/destructed in the correct order.
   rtc::VirtualSocketServer virtual_socket_server_;
   std::unique_ptr<rtc::Thread> network_thread_;
@@ -405,13 +405,13 @@
       } else if (stats.type() == RTCAudioSourceStats::kType) {
         // RTCAudioSourceStats::kType and RTCVideoSourceStats::kType both have
         // the value "media-source", but they are distinguishable with pointer
-        // equality (==). In JavaScript they would be distinguished with |kind|.
+        // equality (==). In JavaScript they would be distinguished with `kind`.
         verify_successful &=
             VerifyRTCAudioSourceStats(stats.cast_to<RTCAudioSourceStats>());
       } else if (stats.type() == RTCVideoSourceStats::kType) {
         // RTCAudioSourceStats::kType and RTCVideoSourceStats::kType both have
         // the value "media-source", but they are distinguishable with pointer
-        // equality (==). In JavaScript they would be distinguished with |kind|.
+        // equality (==). In JavaScript they would be distinguished with `kind`.
         verify_successful &=
             VerifyRTCVideoSourceStats(stats.cast_to<RTCVideoSourceStats>());
       } else if (stats.type() == RTCTransportStats::kType) {
@@ -749,7 +749,7 @@
       verifier.TestMemberIsUndefined(
           media_stream_track.sum_squared_frame_durations);
       // Audio-only members
-      // TODO(hbos): |echo_return_loss| and |echo_return_loss_enhancement| are
+      // TODO(hbos): `echo_return_loss` and `echo_return_loss_enhancement` are
       // flaky on msan bot (sometimes defined, sometimes undefined). Should the
       // test run until available or is there a way to have it always be
       // defined? crbug.com/627816
@@ -1086,7 +1086,7 @@
     verifier.TestMemberIsNonNegative<double>(audio_source.audio_level);
     verifier.TestMemberIsPositive<double>(audio_source.total_audio_energy);
     verifier.TestMemberIsPositive<double>(audio_source.total_samples_duration);
-    // TODO(hbos): |echo_return_loss| and |echo_return_loss_enhancement| are
+    // TODO(hbos): `echo_return_loss` and `echo_return_loss_enhancement` are
     // flaky on msan bot (sometimes defined, sometimes undefined). Should the
     // test run until available or is there a way to have it always be
     // defined? crbug.com/627816
@@ -1100,7 +1100,7 @@
     VerifyRTCMediaSourceStats(video_source, &verifier);
     // TODO(hbos): This integration test uses fakes that doesn't support
     // VideoTrackSourceInterface::Stats. When this is fixed we should
-    // TestMemberIsNonNegative<uint32_t>() for |width| and |height| instead to
+    // TestMemberIsNonNegative<uint32_t>() for `width` and `height` instead to
     // reflect real code.
     verifier.TestMemberIsUndefined(video_source.width);
     verifier.TestMemberIsUndefined(video_source.height);