site: add code line numbers

site/src/routes/docs/[...path]/+page.svelte

@@ -9,7 +9,19 @@
 {JSON.stringify(data.frontmatter)}
 
 <style>
-  .toc :global(p) {
-    margin: 0;
+:global {
+.shiki code {
+  counter-reset: step;
+  counter-increment: step 0;
+}
+.line::before {
+  content: counter(step);
+  counter-increment: step;
+  width: 1rem;
+  margin-right: 1.5rem;
+  display: inline-block;
+  text-align: right;
+  color: rgba(115,138,148,.4);
+}
 }
 </style>

site/src/routes/docs/getting-started/overview.md

@@ -7,6 +7,9 @@ b: 2
 
 ```js
 const abc = 1 + "2";
+const abc = 1 + "2";
+const abc = 1 + "2";
+const abc = 1 + "2";
 ```
 
 ## Step Foo