Move DWC_RIGHT and friends to 0x001-0x004 so nerd fonts can use 0xf000-0xf003. Migrate existing restored state to the new range. Issue 7570.

Also fix a few bugs I found along the way:
- Don't call [NSApp invalidateRestorableState] off the main queue.
- Fix a bug in LineBlock where it didn't save generation when copying, which broke delta encoding.