Documented the `l' tag.

Documented the `l' tag.
(tempo-insert-template): Check for zmacs-regions.
Wrapped it in unwind-protect.
(tempo-save-named): New function.
(tempo-insert-prompt): Added NO-INSERT parameter.
Handles previous values better.  Cleaned up interface.
Check for already saved value.
(tempo-remember-insertion): Function deleted.
(tempo-insert-named): Use tempo-insert if data is not a string.
Use tempo-lookup-named.
(tempo-insert-prompt-compat): New function.
(tempo-lookup-named): New function.