Split markdown parsing and highlighting

src/markdown/tokenizer.rs

@@ -1,16 +1,6 @@
 use std::iter;
 
-use super::span::Span;
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum Heading {
-    H6,
-    H5,
-    H4,
-    H3,
-    H2,
-    H1,
-}
+use super::{Heading, span::Span};
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum TokenKind {