"Insert TIMER into `timer-idle-list'.
This arranges to activate TIMER whenever Emacs is next idle.
If optional argument DONT-WAIT is non-nil, set TIMER to activate
-immediately \(see below\), or at the right time, if Emacs is
+immediately \(see below), or at the right time, if Emacs is
already idle.
REUSE-CELL, if non-nil, is a cons cell to reuse when inserting