Fix capture counting issue

Author: natecook1000

Sources/_StringProcessing/Regex/DSLList.swift

@@ -16,7 +16,10 @@ struct DSLList {
 
   // experimental
   var hasCapture: Bool = false
-  var hasChildren: Bool = false
+  var hasChildren: Bool {
+    (nodes.first?.directChildren ?? 0) > 0
+  }
+  
   var captureList: CaptureList {
     .Builder.build(self)
   }

Tests/RegexTests/CaptureTests.swift

@@ -157,7 +157,7 @@ func captureTest(
   }
 
   // Ensure DSLTree preserves literal captures
-  var dslCapList = ast.dslTree.captureList
+  var dslCapList = DSLList(ast: ast).captureList
   // Peel off the whole match element.
   dslCapList.captures.removeFirst()
   guard dslCapList == capList else {