Use backticks not vertical bars to denote variables in comments for webrtc.gni

Bug: webrtc:12338
Change-Id: I1e3ffdcf5da56d8c831632093fe5267d1c8a4c0d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227034
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34586}
diff --git a/webrtc.gni b/webrtc.gni
index 99d4488..a63f1dd 100644
--- a/webrtc.gni
+++ b/webrtc.gni
@@ -159,9 +159,9 @@
 
   # Enable this to build OpenH264 encoder/FFmpeg decoder. This is supported on
   # all platforms except Android and iOS. Because FFmpeg can be built
-  # with/without H.264 support, |ffmpeg_branding| has to separately be set to a
+  # with/without H.264 support, `ffmpeg_branding` has to separately be set to a
   # value that includes H.264, for example "Chrome". If FFmpeg is built without
-  # H.264, compilation succeeds but |H264DecoderImpl| fails to initialize.
+  # H.264, compilation succeeds but `H264DecoderImpl` fails to initialize.
   # CHECK THE OPENH264, FFMPEG AND H.264 LICENSES/PATENTS BEFORE BUILDING.
   # http://www.openh264.org, https://www.ffmpeg.org/
   #