Update TODO to put a bug number to it.

PiperOrigin-RevId: 244189980
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/BuildEventStreamer.java b/src/main/java/com/google/devtools/build/lib/runtime/BuildEventStreamer.java
index 6a56407..ef4bdb9 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/BuildEventStreamer.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/BuildEventStreamer.java
@@ -634,8 +634,9 @@
     if (event instanceof TargetParsingCompleteEvent) {
       // If there is only one pattern and we have one failed pattern, then we already posted a
       // pattern expanded error, so we don't post the completion event.
-      // TODO(ulfjack): This is brittle. It would be better to always post one PatternExpanded event
-      // for each pattern given on the command line instead of one event for all of them combined.
+      // TODO(b/109727414): This is brittle. It would be better to always post one PatternExpanded
+      // event for each pattern given on the command line instead of one event for all of them
+      // combined.
       return ((TargetParsingCompleteEvent) event).getOriginalTargetPattern().size() == 1
           && !((TargetParsingCompleteEvent) event).getFailedTargetPatterns().isEmpty();
     }