Don't use code font in titles in the dev guide

#minor-release

PiperOrigin-RevId: 426870114

docs/shrinking.md

@@ -104,7 +104,7 @@ ExoPlayer player =
 ~~~
 {: .language-java}
 
-## Custom `MediaSource` instantiation ##
+## Custom MediaSource instantiation ##
 
 If your app is using a custom `MediaSource.Factory` and you want
 `DefaultMediaSourceFactory` to be removed by code stripping, you should pass

docs/ui-components.md

@@ -19,7 +19,7 @@ well as playback controls.
 `StyledPlayerView` has a `setPlayer` method for attaching and detaching (by
 passing `null`) player instances.
 
-## `StyledPlayerView` ##
+## StyledPlayerView ##
 
 `StyledPlayerView` can be used for both video and audio playbacks. It renders
 video and subtitles in the case of video playback, and can display artwork