fix: align Path64/PathD toString formatting with C# 1.4 diff

Co-authored-by: micycle1 <9304234+micycle1@users.noreply.github.com>

Author: Copilot

src/main/java/clipper2/core/Path64.java

@@ -36,7 +36,10 @@ public Path64(Point64... path) {
 	public String toString() {
 		StringBuilder s = new StringBuilder();
 		for (Point64 p : this) {
-			s.append(p.toString()).append(" ");
+			s.append(p.toString()).append(", ");
+		}
+		if (!s.isEmpty()) {
+			s.setLength(s.length() - 2);
 		}
 		return s.toString();
 	}

src/main/java/clipper2/core/PathD.java

@@ -31,7 +31,10 @@ public PathD(List<PointD> path) {
 	public String toString() {
 		StringBuilder s = new StringBuilder();
 		for (PointD p : this) {
-			s.append(p.toString()).append(" ");
+			s.append(p.toString()).append(", ");
+		}
+		if (!s.isEmpty()) {
+			s.setLength(s.length() - 2);
 		}
 		return s.toString();
 	}

src/test/java/clipper2/TestToStringOutput.java

@@ -18,21 +18,21 @@ class TestToStringOutput {
 	@Test
 	void path64ToStringMatchesExistingFormat() {
 		Path64 path = new Path64(new Point64(1, 2), new Point64(3, 4));
-		assertEquals("(1,2)  (3,4)  ", path.toString());
+		assertEquals("(1,2) , (3,4) ", path.toString());
 	}
 
 	@Test
 	void pathDToStringMatchesExistingFormat() {
 		PathD path = new PathD(2);
 		path.add(new PointD(1.5, 2.5));
 		path.add(new PointD(3.5, 4.5));
-		assertEquals("(1.500000,2.500000)  (3.500000,4.500000)  ", path.toString());
+		assertEquals("(1.500000,2.500000) , (3.500000,4.500000) ", path.toString());
 	}
 
 	@Test
 	void paths64ToStringMatchesExistingFormat() {
 		Paths64 paths = new Paths64(new Path64(new Point64(1, 2)));
-		assertEquals("(1,2)  \n", paths.toString());
+		assertEquals("(1,2) \n", paths.toString());
 	}
 
 	@Test
@@ -41,7 +41,7 @@ void pathsDToStringMatchesExistingFormat() {
 		PathD path = new PathD(1);
 		path.add(new PointD(1.5, 2.5));
 		paths.add(path);
-		assertEquals("(1.500000,2.500000)  \n", paths.toString());
+		assertEquals("(1.500000,2.500000) \n", paths.toString());
 	}
 
 	@Test