Document ChangeReportFormatter

Change-Id: I933cafb207ad3c1d18f913ca6b81d8029f29df96
diff --git a/java/com/google/gerrit/server/git/ChangeReportFormatter.java b/java/com/google/gerrit/server/git/ChangeReportFormatter.java
index f897a1d..e0efaef 100644
--- a/java/com/google/gerrit/server/git/ChangeReportFormatter.java
+++ b/java/com/google/gerrit/server/git/ChangeReportFormatter.java
@@ -18,6 +18,7 @@
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Change;
 
+/** Formatter for git command-line progress messages. */
 public interface ChangeReportFormatter {
   @AutoValue
   public abstract static class Input {
diff --git a/java/com/google/gerrit/server/git/DefaultChangeReportFormatter.java b/java/com/google/gerrit/server/git/DefaultChangeReportFormatter.java
index 5866c57..4f6094e 100644
--- a/java/com/google/gerrit/server/git/DefaultChangeReportFormatter.java
+++ b/java/com/google/gerrit/server/git/DefaultChangeReportFormatter.java
@@ -22,7 +22,7 @@
 import com.google.inject.Inject;
 import java.util.Optional;
 
-/** Print a change description for use in git command-line progress. */
+/** Default formatter for change descriptions for use in git command-line progress. */
 public class DefaultChangeReportFormatter implements ChangeReportFormatter {
   private static final int SUBJECT_MAX_LENGTH = 80;
   private static final String SUBJECT_CROP_APPENDIX = "...";