Use @Nullable instead of @CheckForNull.

We'd been using the latter to work around a bug in Kotlin, but that bug was fixed in 1.8.20, and Google has on that version (or later) for a while.

(I think the bug is the flip side of [KT-57996](https://youtrack.jetbrains.com/issue/KT-57996/Usages-of-Foo-Nullable-produce-only-warnings-even-with-Xtype-enhancement-improvements-strict-mode-Xjspecify-annotationsstrict): In KT-57996, Kotlin didn't know that an annotated array was nullable, so it didn't produce the expected warning/error until 1.8.20. Here, Kotlin didn't know that an annotated array was nullable, so it prevented callers from passing null until 1.8.20.)

If Truth users outside Google are still using 1.8.20, they might be affected; I'm not completely sure. It might depend on whether they set `-Xtype-enhancement-improvements-strict-mode`??

RELNOTES=n/a
PiperOrigin-RevId: 532397177

core/src/main/java/com/google/common/truth/Truth.java

@@ -24,7 +24,6 @@
 import com.google.common.collect.Table;
 import java.math.BigDecimal;
 import java.util.Map;
-import javax.annotation.CheckForNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
@@ -198,37 +197,35 @@ public static <T> ObjectArraySubject<T> assertThat(@Nullable T @Nullable [] actu
  return assert_().that(actual);
  }
 
- // TODO(b/269115309): Switch back to @Nullable for Kotlin 1.8.20
-
- public static PrimitiveBooleanArraySubject assertThat(@CheckForNull boolean[] actual) {
+ public static PrimitiveBooleanArraySubject assertThat(boolean @Nullable [] actual) {
  return assert_().that(actual);
  }
 
- public static PrimitiveShortArraySubject assertThat(@CheckForNull short[] actual) {
+ public static PrimitiveShortArraySubject assertThat(short @Nullable [] actual) {
  return assert_().that(actual);
  }
 
- public static PrimitiveIntArraySubject assertThat(@CheckForNull int[] actual) {
+ public static PrimitiveIntArraySubject assertThat(int @Nullable [] actual) {
  return assert_().that(actual);
  }
 
- public static PrimitiveLongArraySubject assertThat(@CheckForNull long[] actual) {
+ public static PrimitiveLongArraySubject assertThat(long @Nullable [] actual) {
  return assert_().that(actual);
  }
 
- public static PrimitiveByteArraySubject assertThat(@CheckForNull byte[] actual) {
+ public static PrimitiveByteArraySubject assertThat(byte @Nullable [] actual) {
  return assert_().that(actual);
  }
 
- public static PrimitiveCharArraySubject assertThat(@CheckForNull char[] actual) {
+ public static PrimitiveCharArraySubject assertThat(char @Nullable [] actual) {
  return assert_().that(actual);
  }
 
- public static PrimitiveFloatArraySubject assertThat(@CheckForNull float[] actual) {
+ public static PrimitiveFloatArraySubject assertThat(float @Nullable [] actual) {
  return assert_().that(actual);
  }
 
- public static PrimitiveDoubleArraySubject assertThat(@CheckForNull double[] actual) {
+ public static PrimitiveDoubleArraySubject assertThat(double @Nullable [] actual) {
  return assert_().that(actual);
  }