Ignore diacritics in 100/700/710 autocomplete in Sources

[jenniferward]

A user reported that it is difficult to find the right name in the 100/700/710 fields in Sources because of diacritics. Of course you can go through the search (magnifying glass), but for a name like Händel the problem becomes apparent after the first letter, and if you are at a place with a large Händel collection then it gets tedious. The user's workaround is copying and pasting an ä from elsewhere.

We've had a lot of tickets regarding diacritics in other fields or areas of Muscat (#306, #305, #690). Can that be applied here?