Apply suggestion to src/main/java/gov/usgs/earthquake/nshmp/data/Sequences.java

src/main/java/gov/usgs/earthquake/nshmp/data/Sequences.java

@@ -102,7 +102,7 @@ class Sequences {
     var combinedMap = xySequences.stream()
         .flatMap(XySequence::stream)
         .collect(Collectors.toMap(
-            (XyPoint xy) -> (double) xy.x(),
+            XyPoint::x,
             (XyPoint xy) -> (double) xy.y(),
             (a, b) -> a + b,
             TreeMap::new));