Add description and recommendation about unicode LTR and RTL marks

### Proposal

Add description and recommendation about unicode LEFT-TO-RIGHT MARK ([U+200E](https://unicode-explorer.com/c/200E)) and RIGHT-TO-LEFT MARK ([U+200F](https://unicode-explorer.com/c/200F)) to https://developer.mozilla.org/en-US/docs/Web/HTML/Element/bdo.

- when to use and not to use
- pros and cons vs \ and \
- accessibility concerns?
-

### Browser support

Firefox

### Tasks

- [ ]

### Dependencies

- [ ]

### Additional information

_No response_

### Are you willing to support this work?

I can provide reviews from the perspective of a learner - but my motivation for the topic is that I myself am not a subject matter expert, and maybe like to read about this subject at a source I trust, like MDN is.