Capture fig-alt= from the first image for use in the listing page

[cgoo4]

When image: is left unspecified in a .qmd YAML header, the first image found is also used for the listing page. This is great as it avoids specifying the image twice when it's wanted in both the listing and as the feature image for the post.

Could the alternative text from the first image also flow through to the listing page? It would avoid the need to specify this twice, i.e. in the YAML as image-alt: and in the inserted image as fig-alt=.

Example where specified twice to appear in both the listing and the post: post in repo
Example where specified in the first image only and doesn't flow to the listing with the image: post in repo

[dragonstyle]

This is a great suggestion- thank you! I'm converting to an issue to track it.

[mcanouil]

Closing as completed and in favour of #3706