Fix CI failure due to contain <U+2028>

```diff
diff --git a/actionpack/lib/action_controller/metal/redirecting.rb b/actionpack/lib/action_controller/metal/redirecting.rb
index a3159c29dd..1836a07d4e 100644
--- a/actionpack/lib/action_controller/metal/redirecting.rb
+++ b/actionpack/lib/action_controller/metal/redirecting.rb
@@ -50,8 +50,8 @@ module Redirecting
     #   redirect_to post_url(@post), status: 301, flash: { updated_post_id: @post.id }
     #   redirect_to({ action: 'atom' }, alert: "Something serious happened")
     #
-    # Statements after redirect_to in our controller get executed, so redirect_to doesn't stop the execution of the function.
-    <U+2028># To terminate the execution of the function immediately after the redirect_to, use return.
+    # Statements after +redirect_to+ in our controller get executed, so +redirect_to+ doesn't stop the execution of the function.
+    # To terminate the execution of the function immediately after the +redirect_to+, use return.
     #   redirect_to post_url(@post) and return
     def redirect_to(options = {}, response_status = {})
       raise ActionControllerError.new("Cannot redirect to nil!") unless options
```

https://travis-ci.org/rails/rails/jobs/207908041#L549

actionpack/lib/action_controller/metal/redirecting.rb

@@ -50,8 +50,8 @@ module Redirecting
     #   redirect_to post_url(@post), status: 301, flash: { updated_post_id: @post.id }
     #   redirect_to({ action: 'atom' }, alert: "Something serious happened")
     #
-    # Statements after redirect_to in our controller get executed, so redirect_to doesn't stop the execution of the function.
-    
# To terminate the execution of the function immediately after the redirect_to, use return.
+    # Statements after +redirect_to+ in our controller get executed, so +redirect_to+ doesn't stop the execution of the function.
+    # To terminate the execution of the function immediately after the +redirect_to+, use return.
     #   redirect_to post_url(@post) and return
     def redirect_to(options = {}, response_status = {})
       raise ActionControllerError.new("Cannot redirect to nil!") unless options