Double tap the status bar to sleep the phone
Requires Xposed Framework installed
Download from the Xposed Repository
Should be compatible with all Android 4.0 and above.
This module is open-source. The sources can be found here
This module is based on this commit
I don't know who first created it since it is cherry-picked but credits goes entirely to the original creator. (If anyone can tell me the original creator, I'll add it in)