(follow-up 79778) Make $wgLang->truncate function consider the length of the ......

(follow-up 79778) Make $wgLang->truncate function consider the length of the ... (ellipsis message) in the truncation length.

The length of this message varries by localization, so the previous solution of telling truncate to truncate 5 bytes
less than needed is not good since this will be too little or too much.

Updated places where its used. Some places I left as is, as it looked like the new behaviour would work fine for them to.
(for example, the autosummary feature - it was cutting off at 200 bytes, which is no where near 250 limit, so I presume that
was for asethic reasons rather then to fit as much in before the db limit).

Will do another commit for extension callers in a moment.