Subtask: Remaining missing `alt` text

[estelle]

Problem statement

There are still 153 missing alt attributes.
Missing alt and surrounding text
Spreadsheet with link and image URL

Proposed solutions

Get volunteers to add alt attributes
Address the ones volunteers don't address

Task list

• Create a list & Spreadsheet.
• Create an issue on MDN
• Recruit volunteers to address the issue
• Address images not addressed by volunteers
• Review PRs
• Maintain/Update the spreadsheet
• Smile!