Restrict cloze shortcut workaround to non-increment case

The workaround is only needed for the option key, and seems to trip
some people up, perhaps due to the order they're pressing/releasing the
keys.

Closes #2090

ts/editor/ClozeButtons.svelte

@@ -87,7 +87,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
     <Shortcut
         keyCombination={incrementKeyCombination}
-        {event}
+        event="keydown"
         on:action={onIncrementCloze}
     />