Update index.rst (aws#2858)

Author: paul-cb

sagemaker-featurestore/index.rst

@@ -9,4 +9,6 @@ Feature Store is a centralized store for features and associated metadata so fea
  feature_store_introduction
  feature_store_kms_key_encryption
  feature_store_client_side_encryption
+ feature_store_securely_store_images
+ feature_store_object_detection_ground_truth
  sagemaker_featurestore_fraud_detection_python_sdk