Normalizes a shortcut string (e.g. a key of a ShortcutActionIdMapping) so that it can be compared with
createHarmonizedShortcutByKeyboardEvent: "+" becomes a space, symbols and synonyms are unified
("⌘"/"meta"/"command" → "cmd", "arrowup" → "up" …), modifiers come first.
Normalizes a shortcut string (e.g. a key of a ShortcutActionIdMapping) so that it can be compared with createHarmonizedShortcutByKeyboardEvent: "+" becomes a space, symbols and synonyms are unified ("⌘"/"meta"/"command" → "cmd", "arrowup" → "up" …), modifiers come first.