docs: replace legacy line‑dot‑left‑horizontal icons with unified dot icon across docs

apps/docs/content/(04-relational)/topological-sort/210-course-schedule-ii.mdx

@@ -1,7 +1,7 @@
 ---
 title: '210. Course Schedule II'
 description: There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [ai, bi] indicates that you must take course bi first if you want to take course ai
-icon: line-dot-left-horizontal
+icon: dot
 sidebar:
   label: 'Course Schedule II'
   badge: 'Medium'