refactor(highlightjs): create separate project

packages/highlightjs/src/index.ts

@@ -0,0 +1 @@
+export * from './lib/highlightjs.js';

packages/highlightjs/src/lib/highlightjs.ts

@@ -0,0 +1,3 @@
+export function highlightjs(): string {
+  return 'highlightjs';
+}