Allow capital letters as hotkeys

[SheldonWBM]

Is your feature request related to a problem? Please describe. I have multiple types of labels and various classes for the same project. As such, I have run out of hotkeys available on the keyboard. For example, shift-R, ctrl-R, or alt-R would allow more hotkeys.

Describe the solution you'd like Ability to use shift, ctrl or alt to increase the number of possible hotkeys.

Describe alternatives you've considered

• I am not using a hotkey for some classes; I can still use the mouse, but it is slightly slower.
• Different projects will be used for the other label types.

Additional context

<RectangleLabels ...>
 <Label value="example" background="#0000ff" hotkey="e"/>
 </RectangleLabels>
 <BrushLabels ...>
  <Label value="example" background="..." hotkey="E"/>
</BrushLabels> 
 <PointLabels ...>
  <Label value="example" background="..." hotkey="alt+e"/>
</PointLabels>