Use SVG icon instead of font icon in modeladmin index view

[jeromelebleu]

This uses the same classes and tags than wagtailadmin/shared/header.html to construct the <header> element and its children.

Contribute to #6107.

[squash-labs]

Manage this branch in Squash

Test this branch here: https://jeromelebleufeatmodeladmin-ind-b64hj.squash.io

[lb-]

@jeromelebleu just one comment for now about editing the changelog, it is blocking the CI runner.

I see there is a larger discussion about icons via #7565 so will let that resolve before looking into this further.

However, as per that discussion I noticed that the fa icons did not work with this change but the built in SVG icons did.

Another idea might be to try to leverage the header shared include even more, although it does require a change to that include.

See patch
idea-modeladmin-header.patch.txt

[jeromelebleu]

Thanks for your comments @lb-!

I see there is a larger discussion about icons via #7565 so will let that resolve before looking into this further.

I think this PR can be treated separately as it does not target the same components.

However, as per that discussion I noticed that the fa icons did not work with this change but the built in SVG icons did.

I don't use fa icons but I understood that wagtail-font-awesome-svg should work, is it the case?

Another idea might be to try to leverage the header shared include even more, although it does require a change to that include.

I don't really see the goal of your proposal; this new template - modeladmin/includes/header_with_search.html - will be included only once, almost everything from wagtailadmin/shared/header.html is overwritten, and modeladmin/index.html already provides some blocks which could permit to extend just some part of it. Could you tell more?

[lb-]

@jeromelebleu thanks for the response above, just ignore that patch suggestion, my thinking was it would be good to leverage the shared includes for all headers but that is not really the purpose of this PR.

[zerolab]

LGTM.

There is a minor (.2px) discrepancy between the final h1 size, but with this version the icon and the heading are better centred next to each other

[lb-]

@jeromelebleu thanks for your work on this and responding to feedback. @zerolab I have taken a look and think this looks good. As per discussion on other items I think we are now all in with SVG icons.

I have updated this branch with release notes, rebased on master and will merge in.