add link to article - line 40

Author: duongau

articles/frontdoor/standard-premium/concept-caching.md

@@ -37,7 +37,7 @@ Front Door caches any chunks as they're received so the entire file doesn't need
 
 ## File compression
 
-Refer to improve performance by compressing files in Azure Front Door.
+Refer to [improve performance by compressing files](how-to-compression.md) in Azure Front Door.
 
 ## Query string behavior