Go back to ALT-Up/Down for speed adjustment

Now that ALT-Up/Down no longer have an effect on window size, they
can go back to their previous bindings of changing the emulated
output speed.

At the same time, remove AltGr support from keysym parsing since it
should be properly handled by the text input stuff now.
14 jobs for master in 8 minutes and 26 seconds (queued for 15 seconds)
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syncterm-windows

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