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

Bug: webrtc:12338
Change-Id: Ifaad29ccb63b0f2f3aeefb77dae061ebc7f87e6c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227024
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34561}

sdk/objc/components/renderer/opengl/RTCEAGLVideoView.m

@@ -31,11 +31,11 @@
 // the method that will trigger the binding of the render
 // buffer. Because the standard behaviour of -[UIView setNeedsDisplay]
 // is disabled for the reasons above, the RTC_OBJC_TYPE(RTCEAGLVideoView) maintains
-// its own |isDirty| flag.
+// its own `isDirty` flag.
 
 @interface RTC_OBJC_TYPE (RTCEAGLVideoView)
 ()<GLKViewDelegate>
-    // |videoFrame| is set when we receive a frame from a worker thread and is read
+    // `videoFrame` is set when we receive a frame from a worker thread and is read
     // from the display link callback so atomicity is required.
     @property(atomic, strong) RTC_OBJC_TYPE(RTCVideoFrame) * videoFrame;
 @property(nonatomic, readonly) GLKView *glkView;
@@ -183,7 +183,7 @@
 // redrawn. This occurs on main thread.
 - (void)glkView:(GLKView *)view drawInRect:(CGRect)rect {
   // The renderer will draw the frame to the framebuffer corresponding to the
-  // one used by |view|.
+  // one used by `view`.
   RTC_OBJC_TYPE(RTCVideoFrame) *frame = self.videoFrame;
   if (!frame || frame.timeStampNs == _lastDrawnFrameTimeStampNs) {
     return;

sdk/objc/components/renderer/opengl/RTCNSGLVideoView.m

@@ -25,7 +25,7 @@
 
 @interface RTC_OBJC_TYPE (RTCNSGLVideoView)
 ()
-    // |videoFrame| is set when we receive a frame from a worker thread and is read
+    // `videoFrame` is set when we receive a frame from a worker thread and is read
     // from the display link callback so atomicity is required.
     @property(atomic, strong) RTC_OBJC_TYPE(RTCVideoFrame) *
     videoFrame;

sdk/objc/components/renderer/opengl/RTCShader.mm

@@ -36,7 +36,7 @@ const char kRTCVertexShaderSource[] =
   "    v_texcoord = texcoord;\n"
   "}\n";
 
-// Compiles a shader of the given |type| with GLSL source |source| and returns
+// Compiles a shader of the given `type` with GLSL source `source` and returns
 // the shader handle or 0 on error.
 GLuint RTCCreateShader(GLenum type, const GLchar *source) {
   GLuint shader = glCreateShader(type);