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

Bug: webrtc:12338
Change-Id: Ia8a9adea291d594e4f59a6a1203a7bfb0758adac
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227165
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34684}
diff --git a/modules/video_coding/packet_buffer_unittest.cc b/modules/video_coding/packet_buffer_unittest.cc
index 97012618..cc1f177 100644
--- a/modules/video_coding/packet_buffer_unittest.cc
+++ b/modules/video_coding/packet_buffer_unittest.cc
@@ -377,9 +377,9 @@
   EXPECT_THAT(packets, SizeIs(7));
 }
 
-// If |sps_pps_idr_is_keyframe| is true, we require keyframes to contain
+// If `sps_pps_idr_is_keyframe` is true, we require keyframes to contain
 // SPS/PPS/IDR and the keyframes we create as part of the test do contain
-// SPS/PPS/IDR. If |sps_pps_idr_is_keyframe| is false, we only require and
+// SPS/PPS/IDR. If `sps_pps_idr_is_keyframe` is false, we only require and
 // create keyframes containing only IDR.
 class PacketBufferH264Test : public PacketBufferTest {
  protected: