📝 docs(concepts): add slug for course overview

- include slug property to improve routing and linking
- enhance accessibility of course overview in the site structure

Author: vicegd

concepts/00-index.mdx

@@ -1,6 +1,7 @@
 ---
 sidebar_position: 0
 title: Course Overview
+slug: /concepts
 ---
 
 import ConceptIndex from '@site/src/components/ConceptIndex';