Since the text properties only takes in one map at a time (as far as I
know), the insert/normal state auxillery maps will conflict with each
other. It's easier to have C-m trigger a function that checks its
state and Does The Right Thing instead.
For now, this one just adds an advice to be able to use "RET" in
insert state during an expansion of a long s-exp.
See eval-print-last-sexp and last-sexp-setup-props.
James Nguyen
Pierre Neidhardt
Fredrik Bergroth