fix azure-storage-blob readme and samples issues (#12511)

Author: v-xuto

sdk/storage/azure-storage-blob/README.md

@@ -188,6 +188,7 @@ Once you've initialized a Client, you can choose from the different types of blo
 ## Examples
 The following sections provide several code snippets covering some of the most common Storage Blob tasks, including:
 
+* [Create a container](#create-a-container "Create a container")
 * [Uploading a blob](#uploading-a-blob "Uploading a blob")
 * [Downloading a blob](#downloading-a-blob "Downloading a blob")
 * [Enumerating blobs](#enumerating-blobs "Enumerating blobs")

sdk/storage/azure-storage-blob/samples/blob_samples_common.py

@@ -140,7 +140,7 @@ def delete_multiple_blobs(self):
         # [END delete_multiple_blobs]
 
         # Delete container
-        blob_service_client.delete_container("containerforbatchblobdeletesasync")
+        blob_service_client.delete_container("containerforbatchblobdelete")
 
     def acquire_lease_on_blob(self):