Allow specifying ellipsis position for text overrun

[timothyqiu]

When strings like paths are too long, usually the ending of the path is more important than the beginning / middle.

I suggest allow specifying ellipsis position: begin / middle / end (default, current behavior).

[Calinou]

I think core text overrun behavior should remain scoped to basic text (Label's text handling is already pretty complex as it is). It may be better to write a custom solution for file paths specifically.