Add detailed description for function multiversioning learning path

Author: madeline-underwood

content/learning-paths/cross-platform/function-multiversioning/_index.md

@@ -5,6 +5,8 @@ minutes_to_complete: 60
 
 who_is_this_for: This is an advanced topic for developers interested in optimizing their C/C++ applications across Arm64 targets.
 
+description: Learn how to optimize C/C++ applications using function multiversioning on Arm64 targets with GCC or LLVM, enabling automatic runtime selection of hardware-optimized function versions.
+
 learning_objectives:
     - Use hardware features to tune your applications at function level.
     - Create multiple versions of C/C++ functions for the targets that you intend to run applications on.