Fix shortcut handling for level three and above shortcuts

Calling `xkb_state_update_mask` with correctly set `depressed_mods` allows xkb to
return keys on level three or above (and not the equivalent level one key).

To preserve level two shortcuts (return equivalent level one key)
`depressed_mods` gets only set, if the pressed key is on level three or above.

Example shortcuts which now will work:
  Shortcut  German Layout (de) [AltGr is a level three switch]
  Ctrl+@    Ctrl+AltGr+Q
  Shift+1   Shift+1  (as before)

  Shortcut  German Neo Layout (de neo) [1] [AltGr is a level five switch]
  Left      AltGr+S

[1] http://neo-layout.org

Task-number: QTBUG-53121
Change-Id: I637a01edc9f2f92a5d3e7a24f5051fb1d3ac2f7f
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

0 files changed, 0 insertions, 0 deletions