It was impossible for keyboard layouts that use AltGr to create certain characters to insert
them in Text and Console.
The keyboard driver in Windows sends left control events when AltGr is pressed. This meant that
Blender thought control was being held, which is a PASS_THROUGH condition for the insert operator
in both editors.
Add testing of keyboard layout for AltGr, both on initialization and WM_INPUTLANGCHANGE.
To remedy AltGr problem, we send now a left control key up event to Blender before further processing
the AltGr key.
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