Fix KeyVault Secrets sample and use the snippets in its README

sdk/keyvault/azure-security-keyvault-secrets/README.md

@@ -80,9 +80,11 @@ For detailed samples please review the samples provided.
 
 First step is to create  a SecretClient.
 
+<!-- @insert_snippet: SecretSample1CreateCredential -->
 ```cpp
 auto const keyVaultUrl = std::getenv("AZURE_KEYVAULT_URL");
 auto credential = std::make_shared<Azure::Identity::DefaultAzureCredential>();
+
 // create client
 SecretClient secretClient(keyVaultUrl, credential);
 ```
@@ -91,6 +93,7 @@ SecretClient secretClient(keyVaultUrl, credential);
 
 We call the secret client to create a secret.
 
+<!-- @insert_snippet: SecretSample1CreateSecret -->
 ```cpp
 std::string secretName("MySampleSecret");
 std::string secretValue("my secret value");
@@ -102,34 +105,36 @@ secretClient.SetSecret(secretName, secretValue);
 
 We retrieve a secret by name.
 
+<!-- @insert_snippet: SecretSample1GetSecret -->
 ```cpp
 // get secret
 KeyVaultSecret secret = secretClient.GetSecret(secretName).Value;
 
 std::string valueString = secret.Value.HasValue() ? secret.Value.Value() : "NONE RETURNED";
-std::cout << "Secret is returned with name " << secret.Name << " and value "
-          << valueString << std::endl;
+std::cout << "Secret is returned with name " << secret.Name << " and value " << valueString
+          << std::endl;
 ```
 
 ### Update a secret
 
 Updating an existing secret
 
+<!-- @insert_snippet: SecretSample1UpdateSecretProperties -->
 ```cpp
 // change one of the properties
 secret.Properties.ContentType = "my content";
 // update the secret
 KeyVaultSecret updatedSecret = secretClient.UpdateSecretProperties(secret.Properties).Value;
-std::string updatedValueString = updatedSecret.Value.HasValue() ? updatedSecret.Value.Value()
-                                                                : "NONE RETURNED";
-std::cout << "Secret's content type is now " << updatedValueString
-          << std::endl;
+std::string updatedValueString
+    = updatedSecret.Value.HasValue() ? updatedSecret.Value.Value() : "NONE RETURNED";
+std::cout << "Secret's content type is now " << updatedValueString << std::endl;
 ```
 
 ### Delete a secret
 
 Delete an existing secret.
 
+<!-- @insert_snippet: SecretSample1DeleteSecret -->
 ```cpp
 // start deleting the secret
 DeleteSecretOperation operation = secretClient.StartDeleteSecret(secret.Name);
@@ -147,6 +152,7 @@ secretClient.PurgeDeletedSecret(secret.Name);
 
 Delete and Purge a secret.
 
+<!-- @insert_snippet: SecretSample1DeleteSecret -->
 ```cpp
 // start deleting the secret
 DeleteSecretOperation operation = secretClient.StartDeleteSecret(secret.Name);
@@ -164,6 +170,7 @@ secretClient.PurgeDeletedSecret(secret.Name);
 
 List all the secrets in keyvault. 
 
+<!-- @insert_snippet: SecretSample4ListAllSecrets -->
 ```cpp
 // get all the versions of a secret
 for (auto secretsVersion = secretClient.GetPropertiesOfSecretsVersions(secret1.Name);

sdk/keyvault/azure-security-keyvault-secrets/samples/sample1-basic-operations/sample1_basic_operations.cpp

@@ -21,8 +21,8 @@ using namespace std::chrono_literals;
 
 int main()
 {
-  auto const keyVaultUrl = std::getenv("AZURE_KEYVAULT_URL");
   // @begin_snippet: SecretSample1CreateCredential
+  auto const keyVaultUrl = std::getenv("AZURE_KEYVAULT_URL");
   auto credential = std::make_shared<Azure::Identity::DefaultAzureCredential>();
 
   // create client