Update:
With the recent redesign of the review queues, this script has become obsolete.
Screenshot
About
Unlike other review queues, the suggested edits queue does not have a heading that indicates whether the edited post is a question or answer. This information is only displayed in small gray colored text, next to the author's profile picture (relevant MSE post).
This user script detects whether a post is a question or an answer, and adds this information as a new heading, similar to the other review queues. It also highlights whether a question is closed, which is usually only indicated in the displayed question title.
Installation
I uploaded the script to GitHub.
Click here for a direct installation link.
After enabling the script in your user script manager (I tested with Tampermonkey and Greasemonkey), it should automatically insert the heading whenever you visit the suggested edits queue.
Contact
If you experience any bugs or have ideas for improvements, please let me know!
