Dart SDK Spelling b, c, and d.

sdk/lib/_internal/js_runtime/lib/js_array.dart

Index: sdk/lib/_internal/js_runtime/lib/js_array.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/js_array.dart b/sdk/lib/_internal/js_runtime/lib/js_array.dart
index 1118cc60fbe817d240ebf74f36f19d71c7ddd127..460e76649888db1000cb50c0329a71da32b6da9d 100644
--- a/sdk/lib/_internal/js_runtime/lib/js_array.dart
+++ b/sdk/lib/_internal/js_runtime/lib/js_array.dart
@@ -634,7 +634,7 @@ class JSArray<E> extends Interceptor implements List<E>, JSIndexable {
  * getInterceptor always returns JSArray.  We should consider pushing the
  * 'isGrowable' and 'isMutable' checks into the getInterceptor implementation so
  * these classes can have specialized implementations. Doing so will challenge
- * many assuptions in the JS backend.
+ * many assumptions in the JS backend.
  */
 class JSMutableArray<E> extends JSArray<E> implements JSMutableIndexable {}