markdown it attrs with slashes dont work

Attrs does not like ‘/’ characters in its classes, so to use some tailwind classes with custom values we must make new classes in our tailwind input css.

.cinematic {
  @apply aspect-[2.39/1];
}

Given the following markdown with attrs added to the image and to the paragraph block.

![screenshot-2025-01-31T14-50-00-094Z.png](https://dropper.waylonwalker.com/api/file/50cfa8dc-9d46-4f02-877b-688fa5510a83.png){.aspect-[2.39/1]}

![screenshot-2025-01-31T14-50-00-094Z.png](https://dropper.waylonwalker.com/api/file/50cfa8dc-9d46-4f02-877b-688fa5510a83.png){.cinematic}

{.cinematic}
![screenshot-2025-01-31T14-50-00-094Z.png](https://dropper.waylonwalker.com/api/file/50cfa8dc-9d46-4f02-877b-688fa5510a83.png)

We get the following output with only the middle one working correctly.

{.aspect-[2.39/1]}

{.cinematic}

The inline version of `.cinematic` works, but `.aspect-[2.39/1]` does not,