Spelling fixes e to i.

pkg/kernel/lib/ast.dart

Index: pkg/kernel/lib/ast.dart
diff --git a/pkg/kernel/lib/ast.dart b/pkg/kernel/lib/ast.dart
index dcc0285ef761ae0f0e3c3e146f4b52626fbc384f..ef87e1dbe76c50a7752f4cbb6b2e511d2a8bb127 100644
--- a/pkg/kernel/lib/ast.dart
+++ b/pkg/kernel/lib/ast.dart
@@ -1551,7 +1551,7 @@ abstract class Expression extends TreeNode {
   /// Should only be used on code compiled in strong mode, as this method
   /// assumes the IR is strongly typed.
   ///
-  /// This method futhermore assumes that the type of the expression actually
+  /// This method furthermore assumes that the type of the expression actually
   /// is a subtype of (some instantiation of) the given [superclass].
   /// If this is not the case, either an exception is thrown or the raw type of
   /// [superclass] is returned.