Accessibility improvements

[coliff]

A minor accessibility improvement:

• Adds main landmark (this is particularly helpful for screen readers - tested with NVDA on Windows)

Fixes this issue: https://dequeuniversity.com/rules/axe/4.8/landmark-one-main

Note: I didn't add <article> to blog posts in my original commit due to multiple h1s on the page which caused tests to fail.

[XhmikosR]

This breaks HTML validation, please have a look at tests @coliff

[coliff]

Oh, there are multiple h1s on the homepage. I think we can change the post titles here from h1 to h2s (but add h1 class so styling is the same).

command used: java -jar "/home/runner/work/blog/blog/node_modules/vnu-jar/build/dist/vnu.jar" --asciiquotes --skip-non-html --Werror --filterpattern "Duplicate ID.*|The first occurrence of ID.*|Trailing slash on void elements has no effect and interacts badly with unquoted attribute values.*" _site/

Not sure about that part though, I didn't touch anything with an id.

[XhmikosR]

Not sure about that part though, I didn't touch anything with an id.

It's not that you touched anything, it's the command we execute when vnu.jar runs :)

[coliff]

ah I see now - thanks. Fixing the multiple h1s would take a bit more time (which I don't have right now) as the corresponding CSS for the headings need updating (and the h2s within the article would need to be demoted to h3s etc).

You could either add this error to the skip list and approve/merge as it is or I can come back to it later or maybe I'll remove the part which causes the error. (surprised that changing a div to a main or article would cause the error though).

[julien-deramond]

Thanks for the PR @coliff
LGTM, it's what we do too in the main documentation