pub(crate) fn new_empty(
        _content: impl AsRef<str>,
        span: Span,
        variant: CommentVariant,
    ) -> Self {
        Self {
            // Track what kind of comment the literal is
            variant,
            span,
            // .
            rendered: String::new(),
            pre: 0,
            post: 0,
            len_in_chars: 0,
            len_in_bytes: 0,
        }
    }
Create an empty comment.

Prime use case is for `#[doc = foo!()]` cases.
doc-chunks/src/literal.rs