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/test/audioproc_float.h b/api/test/audioproc_float.h
index fec2ad1..1ef1c98 100644
--- a/api/test/audioproc_float.h
+++ b/api/test/audioproc_float.h
@@ -23,12 +23,12 @@
 // utility can be used to simulate the audioprocessing module using a recording
 // (either an AEC dump or wav files), and generate the output as a wav file.
 // Any audio_processing object specified in the input is used for the
-// simulation. The optional |audio_processing| object provides the
+// simulation. The optional `audio_processing` object provides the
 // AudioProcessing instance that is used during the simulation. Note that when
 // the audio_processing object is specified all functionality that relies on
 // using the AudioProcessingBuilder is deactivated, since the AudioProcessing
 // object is already created and the builder is not used in the simulation. It
-// is needed to pass the command line flags as |argc| and |argv|, so these can
+// is needed to pass the command line flags as `argc` and `argv`, so these can
 // be interpreted properly by the utility. To see a list of all supported
 // command line flags, run the executable with the '--help' flag.
 int AudioprocFloat(rtc::scoped_refptr<AudioProcessing> audio_processing,
@@ -38,10 +38,10 @@
 // This is an interface for the audio processing simulation utility. This
 // utility can be used to simulate the audioprocessing module using a recording
 // (either an AEC dump or wav files), and generate the output as a wav file.
-// The |ap_builder| object will be used to create the AudioProcessing instance
-// that is used during the simulation. The |ap_builder| supports setting of
+// The `ap_builder` object will be used to create the AudioProcessing instance
+// that is used during the simulation. The `ap_builder` supports setting of
 // injectable components, which will be passed on to the created AudioProcessing
-// instance. It is needed to pass the command line flags as |argc| and |argv|,
+// instance. It is needed to pass the command line flags as `argc` and `argv`,
 // so these can be interpreted properly by the utility.
 // To get a fully-working audioproc_f utility, all that is needed is to write a
 // main function, create an AudioProcessingBuilder, optionally set custom
@@ -56,9 +56,9 @@
 // Interface for the audio processing simulation utility, which is similar to
 // the one above, but which adds the option of receiving the input as a string
 // and returning the output as an array. The first three arguments fulfill the
-// same purpose as above. Pass the |input_aecdump| to provide the content of an
+// same purpose as above. Pass the `input_aecdump` to provide the content of an
 // AEC dump file as a string. After the simulation is completed,
-// |processed_capture_samples| will contain the the samples processed on the
+// `processed_capture_samples` will contain the the samples processed on the
 // capture side.
 int AudioprocFloat(std::unique_ptr<AudioProcessingBuilder> ap_builder,
                    int argc,