Search enhancement: accented characters

Might be useful to provide a mechanism for users to select from a list of accented characters. Selected character is inserted into the search filter and the character selector is cleared.

The list of characters might need to be language-specific? E.g. the "obvious" first cut would be Western European characters, but for (e.g.) Middle Eastern users, the list might be very different.

Start by locating the search filter and its surrounding Windows Forms UI in the Ancestral-Tree application. Clarify the initial character list, how language-specific lists should work, and the expected behavior after selection. Done means users can select an accented character, see it inserted into the search filter, and have the selector cleared.

Written by the indexing model from the issue text.