Remove resolved TODO

This has been done for (almost) all span types.

PiperOrigin-RevId: 405588294

Author: andrewlewis

testutils/src/main/java/com/google/android/exoplayer2/testutil/truth/SpannedSubject.java

@@ -52,7 +52,6 @@
 import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /** A Truth {@link Subject} for assertions on {@link Spanned} instances containing text styling. */
-// TODO: add support for more Spans i.e. all those used in androidx.media3.common.text.
 public final class SpannedSubject extends Subject {
 
   @Nullable private final Spanned actual;