Feature request: Allow customizing substitute statement on Max Authors

[zbalkan]

Currently, when Max Authors option is set, it allows replacing the truncated authors with "and others". However IEEE Reference Style Guide has a note on the topic:

IEEE publications must list names of all authors, up to six names. If there are more than six names listed, use the primary author’s name followed by "et al."

While it is simple to do a find-and-replace for "and others" to "et al", it is a nice-to-have in the editor to be able to pick the substitute statement on truncation.