refactor: simplify line filling a bit

src/node/markdown/plugins/highlight.ts

@@ -162,10 +162,8 @@ export async function highlight(
         },
         {
           name: 'vitepress:empty-line',
-          pre(hast) {
+          code(hast) {
-            hast.children.forEach((code) => {
+            hast.children.forEach((span) => {
-              if (code.type === 'element' && code.tagName === 'code') {
-                code.children.forEach((span) => {
               if (
                 span.type === 'element' &&
                 span.tagName === 'span' &&
@@ -182,8 +180,6 @@ export async function highlight(
               }
             })
           }
-            })
-          }
         },
         ...userTransformers
       ],