Find change log file, and add an entry for today and an item for this file.
Optional arg WHOAMI (interactive prefix) non-nil means prompt for user
name and email (stored in `add-log-full-name' and `add-log-mailing-address').
Second arg FILE-NAME is file name of the change log.
If nil, use the value of `change-log-default-name'.
Third arg OTHER-WINDOW non-nil means visit in other window.
Fourth arg NEW-ENTRY non-nil means always create a new entry at the front;
never append to an existing entry. Option `add-log-keep-changes-together'
otherwise affects whether a new entry is created.
Fifth arg PUT-NEW-ENTRY-ON-NEW-LINE non-nil means that if a new
entry is created, put it on a new line by itself, do not put it
after a comma on an existing line.
Option `add-log-always-start-new-record' non-nil means always create a
new record, even when the last record was made on the same date and by
the same person.
The change log file can start with a copyright notice and a copying
permission notice. The first blank line indicates the end of these
Today's date is calculated according to `add-log-time-zone-rule' if
non-nil, otherwise in local time. (fn &optional WHOAMI FILE-NAME OTHER-WINDOW NEW-ENTRY PUT-NEW-ENTRY-ON-NEW-LINE)