Add comment explaining important_outputs connection to ResultStore.

RELNOTES: None.
PiperOrigin-RevId: 450504165
diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventProtocolOptions.java b/src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventProtocolOptions.java
index 2ffb42f..0333f0c 100644
--- a/src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventProtocolOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventProtocolOptions.java
@@ -23,13 +23,14 @@
 public class BuildEventProtocolOptions extends OptionsBase {
 
   @Option(
-    name = "legacy_important_outputs",
-    defaultValue = "true",
-    documentationCategory = OptionDocumentationCategory.LOGGING,
-    effectTags = {OptionEffectTag.AFFECTS_OUTPUTS},
-    help = "Use this to suppress generation of the legacy important_outputs field in the "
-        + "TargetComplete event."
-  )
+      name = "legacy_important_outputs",
+      defaultValue = "true",
+      documentationCategory = OptionDocumentationCategory.LOGGING,
+      effectTags = {OptionEffectTag.AFFECTS_OUTPUTS},
+      help =
+          "Use this to suppress generation of the legacy important_outputs field in the "
+              + "TargetComplete event. important_outputs are required for Bazel to ResultStore "
+              + "integration.")
   public boolean legacyImportantOutputs;
 
   @Option(