Reference IMA language code bug

PiperOrigin-RevId: 343883034

extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsLoader.java

@@ -735,11 +735,12 @@ public final class ImaAdsLoader implements Player.EventListener, AdsLoader {
 
     /**
      * Returns a language code that's suitable for passing to {@link ImaSdkSettings#setLanguage} and
-     * corresponds to the device's {@link Locale#getDefault() default Locale}.
+     * corresponds to the device's {@link Locale#getDefault() default Locale}. IMA will fall back to
+     * its default language code ("en") if the value returned is unsupported.
      */
     // TODO: It may be possible to define a better mapping onto IMA's supported language codes. See:
     // https://developers.google.com/interactive-media-ads/docs/sdks/android/client-side/localization.
-    // IMA will fall back to its default language code ("en") if the value returned is unsupported.
+    // [Internal ref: b/174042000] will help if implemented.
     private static String getImaLanguageCodeForDefaultLocale() {
       return Util.splitAtFirst(Util.getSystemLanguageCodes()[0], "-")[0];
     }