Draft guidance on meaningful icons and alt-text

[alex-hull]

Related to issue #6194

Draft guidance that describes when users should implement alt-text for icons.

• [ ] Do some very brief research on what the community says around this issues
• [ ] Rough draft of guidance, document link here in issue

[annepetersen]

Guidance and recommended change of previews, probably.

We may want to close this related issue if this replaces it