#3 Remove contents tag for neovan files

Currently HTML in '.neovan' files is put inside of a tag. Remove this.

When writing HTML it should not be inside of any tag at all. Like Svelte, only JS and CSS require their own containing tags.

When implementing, it should just strip the js and css out, then, what is left over will be the HTML

Solved this a bit differently. Decided to use @ symbol instead for the main tags, similar to components.