Document that detail messages should not be filtered out (#146)

Author: wmdietl

src/test/java/tests/ConformanceTest.java

@@ -144,6 +144,8 @@ private static ImmutableSet<ReportedFact> analyze(
     return result.getUnexpectedDiagnostics().stream()
         .map(d -> DetailMessage.parse(d.getMessage(), testDirectory))
         .filter(Objects::nonNull)
+        // Do not filter out messages without details.
+        // .filter(DetailMessage::hasDetails)
         .map(DetailMessageReportedFact::new)
         .collect(toImmutableSet());
   }