Add @since tags for the first batch of Java-8-related APIs.

(Those are the ones from cl/597243015, cl/598637400, and cl/598664192.)

RELNOTES=n/a
PiperOrigin-RevId: 599916105

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

@@ -39,6 +39,7 @@
  * stream before asserting on it.
  *
  * @author Kurt Alfred Kluever
+ * @since 1.3.0 (previously part of {@code truth-java8-extension})
  */
 @SuppressWarnings({
   "deprecation", // TODO(b/134064106): design an alternative to no-arg check()

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

@@ -39,6 +39,7 @@
  * stream before asserting on it.
  *
  * @author Kurt Alfred Kluever
+ * @since 1.3.0 (previously part of {@code truth-java8-extension})
  */
 @SuppressWarnings({
   "deprecation", // TODO(b/134064106): design an alternative to no-arg check()

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

@@ -25,6 +25,7 @@
  * Propositions for Java 8 {@link OptionalDouble} subjects.
  *
  * @author Ben Douglass
+ * @since 1.3.0 (previously part of {@code truth-java8-extension})
  */
 @SuppressWarnings("Java7ApiChecker") // used only from APIs with Java 8 in their signatures
 @IgnoreJRERequirement

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

@@ -25,6 +25,7 @@
  * Propositions for Java 8 {@link OptionalInt} subjects.
  *
  * @author Ben Douglass
+ * @since 1.3.0 (previously part of {@code truth-java8-extension})
  */
 @SuppressWarnings("Java7ApiChecker") // used only from APIs with Java 8 in their signatures
 @IgnoreJRERequirement

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

@@ -25,6 +25,7 @@
  * Propositions for Java 8 {@link OptionalLong} subjects.
  *
  * @author Ben Douglass
+ * @since 1.3.0 (previously part of {@code truth-java8-extension})
  */
 @SuppressWarnings("Java7ApiChecker") // used only from APIs with Java 8 in their signatures
 @IgnoreJRERequirement

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

@@ -25,6 +25,7 @@
  * Propositions for Java 8 {@link Optional} subjects.
  *
  * @author Christian Gruber
+ * @since 1.3.0 (previously part of {@code truth-java8-extension})
  */
 @SuppressWarnings("Java7ApiChecker") // used only from APIs with Java 8 in their signatures
 @IgnoreJRERequirement

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

@@ -19,7 +19,11 @@
 import com.google.j2objc.annotations.J2ObjCIncompatible;
 import java.nio.file.Path;
 
-/** Assertions for {@link Path} instances. */
+/**
+ * Assertions for {@link Path} instances.
+ *
+ * @since 1.3.0 (previously part of {@code truth-java8-extension})
+ */
 @GwtIncompatible
 @J2ObjCIncompatible
 @J2ktIncompatible

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

@@ -170,6 +170,10 @@ public final TableSubject that(@Nullable Table<?, ?, ?> actual) {
     return new TableSubject(metadata(), actual);
   }
 
+  /**
+   * @since 1.3.0 (with access to {@link OptionalSubject} previously part of {@code
+   *     truth-java8-extension})
+   */
   @SuppressWarnings({
     "Java7ApiChecker", // no more dangerous that wherever the user got the Optional
     "NullableOptional", // Truth always accepts nulls, no matter the type
@@ -178,6 +182,10 @@ public final OptionalSubject that(@Nullable Optional<?> actual) {
     return new OptionalSubject(metadata(), actual, "optional");
   }
 
+  /**
+   * @since 1.3.0 (with access to {@link StreamSubject} previously part of {@code
+   *     truth-java8-extension})
+   */
   @SuppressWarnings("Java7ApiChecker") // no more dangerous that wherever the user got the Stream
   public final StreamSubject that(@Nullable Stream<?> actual) {
     return new StreamSubject(metadata(), actual);

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

@@ -43,6 +43,7 @@
  * stream before asserting on it.
  *
  * @author Kurt Alfred Kluever
+ * @since 1.3.0 (previously part of {@code truth-java8-extension})
  */
 @SuppressWarnings("Java7ApiChecker") // used only from APIs with Java 8 in their signatures
 @IgnoreJRERequirement

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

@@ -253,12 +253,18 @@ public static TableSubject assertThat(@Nullable Table<?, ?, ?> actual) {
 
   @SuppressWarnings("Java7ApiChecker") // no more dangerous that wherever the user got the Optional
   @GwtIncompatible // creates ambiguities (Eclipse bug 577808 or similar?)
+  /**
+   * @since 1.3.0 (present in {@link Truth8} since before 1.0)
+   */
   public static <T> OptionalSubject assertThat(@Nullable Optional<T> actual) {
     return assert_().that(actual);
   }
 
   @SuppressWarnings("Java7ApiChecker") // no more dangerous that wherever the user got the Stream
   @GwtIncompatible // creates ambiguities (Eclipse bug 577808 or similar?)
+  /**
+   * @since 1.3.0 (present in {@link Truth8} since before 1.0)
+   */
   public static <T extends @Nullable Object> StreamSubject assertThat(@Nullable Stream<T> actual) {
     return assert_().that(actual);
   }