Proposal: Support neutral characters for marked items in checklists

Currently, the only way to mark an item in a checklist is to use the Latin letter x.

Since this character is a strong character with LTR direction, it becomes annoying to make a checklist with RTL items because any attempt to mark its items turns the line into LTR (the first strong character of the line becomes x)

There shouldn’t be any harm in supporting neutral characters such as * or + (I personally prefer +), but I would suggest supporting both or even more.

- [ ] unmarked item
- [x] mark with x
- [+] mark with + - currently not supported
- [*] mark with * - currently not supported


I just noticed that CommonMark does not support checklists at all!
Then I guess this proposal is pointless for the time being.