bug(mac): label OSK keys to match the Mac physical keyboard

### Describe the bug

The OSK in Keyman for Mac should resemble a Mac keyboard so that users can easily map the keys they are typing to the ones that appear in the OSK. Since 1984, the Mac has always had option keys instead of alt keys, so it would be best to rename them on the OSK.

Other special keys can also be modified to match how they appear on the physical keyboard, such as using all lower case letters, spelling out 'control' rather than abbreviating and using 'return' and 'shift' instead of symbols. There have been slight variations in the keyboard labels since the Mac was first introduced, but they have seen little change in many years.