auto-composition-mode is an interactive compiled Lisp function in `composite.el'.

(auto-composition-mode &optional ARG)

Toggle Auto Composition mode.
With a prefix argument ARG, enable Auto Composition mode if ARG
is positive, and disable it otherwise. If called from Lisp,
enable the mode if ARG is omitted or nil.

When Auto Composition mode is enabled, text characters are
automatically composed by functions registered in

You can use `global-auto-composition-mode' to turn on
Auto Composition mode in all buffers (this is the default).