Add a link to config json-schema

Author: lenkis

doc/code_snippets/snippets/config/instances.enabled/instance_scope/config.yaml

@@ -1,3 +1,4 @@
+# yaml-language-server: $schema=https://download.tarantool.org/tarantool/schema/config.schema.json
 groups:
   group001:
     replicasets:
@@ -6,4 +7,4 @@ groups:
           instance001:
             iproto:
               listen:
-              - uri: '127.0.0.1:3301'
+              - uri: '127.0.0.1:3301'