change second rule 3 comment

Co-authored-by: Mythicaeda <[email protected]>

db-tests/src/test/java/gov/nasa/jpl/aerie/database/ExternalEventTests.java

@@ -1240,8 +1240,7 @@ void rule3_basic() throws SQLException {
       }
 
       /**
-       * Tests rule 3, wherein a superseding source nullifies anything in A based on the _start time_ of the event
-       *    occurring during the range of a newer source, but with an entirely empty source.
+       * A completely empty source will still supercede earlier sources.
        *
        *    A:    +a+aaaaa
        *    B:  ++++++++