Update diagnostics for EXTENSION_OVERRIDE_WITH_CASCADE.

Somehow bots did not catch it.

R=brianwilkerson@google.com

Change-Id: I4fa29f662ffbf541b2fb76d3449c3e69cc1e48bf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/160783
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
diff --git a/pkg/analyzer/lib/src/error/codes.dart b/pkg/analyzer/lib/src/error/codes.dart
index 56baebc..d45a6c0 100644
--- a/pkg/analyzer/lib/src/error/codes.dart
+++ b/pkg/analyzer/lib/src/error/codes.dart
@@ -2897,7 +2897,7 @@
   //   void m() {}
   // }
   // f() {
-  //   E(3)[!..!]m();
+  //   [!E!](3)..m();
   // }
   // ```
   //
diff --git a/pkg/analyzer/tool/diagnostics/diagnostics.md b/pkg/analyzer/tool/diagnostics/diagnostics.md
index adfb44f..e0b0db5 100644
--- a/pkg/analyzer/tool/diagnostics/diagnostics.md
+++ b/pkg/analyzer/tool/diagnostics/diagnostics.md
@@ -2364,7 +2364,7 @@
   void m() {}
 }
 f() {
-  E(3)[!..!]m();
+  [!E!](3)..m();
 }
 {% endprettify %}