refactor: Update header formatting in benchmark visualization example for consistency

Author: selimfirat

examples/benchmarks/plot_visualization_example.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
-"""Benchmark Visualization Example
-
+"""
+=================================
+Benchmark Visualization Example
 =================================
 
 This example demonstrates comprehensive benchmark result visualization in Kaira,