Updating the AzureRM Backend Documentation (#15990)

* Updating to reference this has been renamed

* Clarifying Blob Storage

website/docs/backends/types/azurerm.html.md

@@ -3,10 +3,11 @@ layout: "backend-types"
 page_title: "Backend Type: azurerm"
 sidebar_current: "docs-backends-types-standard-azurerm"
 description: |-
-  Terraform can store state remotely in Azure Storage.
+  Terraform can store state remotely in Azure Blob Storage.
+
 ---
 
-# azurerm
+# azurerm (formerly azure)
 
 **Kind: Standard (with state locking)**
 

website/layouts/backend-types.erb

@@ -27,7 +27,7 @@
             <a href="/docs/backends/types/artifactory.html">artifactory</a>
           </li>
           <li<%= sidebar_current("docs-backends-types-standard-azurerm") %>>
-            <a href="/docs/backends/types/azurerm.html">azure</a>
+            <a href="/docs/backends/types/azurerm.html">azurerm (_formerly `azure`_)</a>
           </li>
           <li<%= sidebar_current("docs-backends-types-standard-consul") %>>
             <a href="/docs/backends/types/consul.html">consul</a>