text: Handle key events in the target phase

text: Handle key events in the target phase

This makes sure that we do actual key input right
in the middle between all the capture and bubble
event controllers, and are not dependent on the
ordering of those controllers.

The bug that triggered this change was that the
shortcut for activation (Enter) was getting triggered
before the key input, causing Ctrl-Shift-u hex
to stop working, since it never received the enter
to commit the sequence.