Fix typo in ActionView::OutputBuffer

Fix: rails#45789

I shouldn't commit this early -_-

Author: byroot

actionview/lib/action_view/buffers.rb

@@ -50,7 +50,7 @@ def <<(value)
       end
       self
     end
-    alias :concat, :<<
+    alias :concat :<<
     alias :append= :<<
 
     def safe_concat(value)