Add redis cache to docs nav menu

docs/en/Redis-Cache.md

@@ -36,4 +36,8 @@ Configure<RedisCacheOptions>(options =>
 {
     //...
 });
-````
+````
+
+## See Also
+
+* [Caching](Caching.md)

docs/en/docs-nav.json

@@ -156,7 +156,13 @@
         },
         {
           "text": "Caching",
-          "path": "Caching.md"
+          "path": "Caching.md",
+          "items": [
+            {
+              "text": "Redis Cache",
+              "path": "Redis-Cache.md"
+            }
+          ]
         },
         {
           "text": "Logging",