I have no idea on how to suggest update to the CB Manual.
I did figure out how to turn on/off the Line numbers and it agrees with your proposed change.
Edit: The CB Manual was written by a Education group who used CB in the classroom; I have no idea who is maintaining it.
Edit: I prefer the below style in my posts and the Wiki.
"Settings" -> "Editor"
"General Settings"
Tab "Editor Settings"
Section "Other Options"
Checkbox "Show Line Numbers"
Tim S.