Change getRange to sublist. Make getRange deprecated.

sdk/lib/_internal/dartdoc/lib/src/markdown/inline_parser.dart

Index: sdk/lib/_internal/dartdoc/lib/src/markdown/inline_parser.dart
diff --git a/sdk/lib/_internal/dartdoc/lib/src/markdown/inline_parser.dart b/sdk/lib/_internal/dartdoc/lib/src/markdown/inline_parser.dart
index 5faebf289c675e64411461c82a348e020a8baaac..26c94848117f02613d3229924f5c528c1e2b3fe2 100644
--- a/sdk/lib/_internal/dartdoc/lib/src/markdown/inline_parser.dart
+++ b/sdk/lib/_internal/dartdoc/lib/src/markdown/inline_parser.dart
@@ -387,8 +387,7 @@ class TagState {
     int index = parser._stack.indexOf(this);
 
     // Remove the unmatched children.
-    final unmatchedTags = parser._stack.getRange(index + 1,
-        parser._stack.length - index - 1);
+    final unmatchedTags = parser._stack.sublist(index + 1);
     parser._stack.removeRange(index + 1, parser._stack.length - index - 1);
 
     // Flatten them out onto this tag.