QLineEdit closes input method on enter key press, TextInput
should also do the same. Commit and hide input method on enter
key. When Qt::ImhMultiLine input method hint set only commit.

Task-number: QTBUG-37850
Change-Id: I5a06e3eb777d7f794dd1493b307f0b05a2caf281
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>