Add "change" and "removed" parameters to TextEdit's text_changed and text_set signals

[InkONat]

It would be nice to know what text was added or removed (and being able to know if it was an addition or removal by addition and removed) from a TextEdit. It would make, for example, limiting the characters you can input in the text easier.

Maybe this removed parameter could be added to LineEdit's text_changed and text_submitted signals too?