Now the man page does not document anywhere that editline(7) is used by the sh(1) for the command line editing. There is a reference to editrc(5), but it's not very obvious and mentioned only once, in the bind command description. Meanwhile, editline(7) does a good job on documenting editor commands and modes, which are mentioned in the sh(1) page several times.
Also, I believe that most users, if want to find more information about, say, keybindings for searching through the shell history, would expect to find that in the sh(1) page, since shell is the program, where they use these keybindings. It would be easier for them to come across editline(7) if this man page will be mentioned in several places.