Fix typo

Azure key vault -> Azure Key Vault

Author: changeworld

articles/backup/install-mars-agent.md

@@ -148,7 +148,7 @@ To install and register  the MARRS agent, follow these steps:
    If you are running into issues during vault registration, see the [troubleshooting guide](backup-azure-mars-troubleshoot.md#invalid-vault-credentials-provided).
 
    >[!Note]
-   >We recommend to save your passphrase in an alternate secure location, such as the Azure key vault. Microsoft can't recover the data without the passphrase. [Learn](save-backup-passphrase-securely-in-azure-key-vault.md) how to store a secret in a Key Vault.
+   >We recommend to save your passphrase in an alternate secure location, such as the Azure Key Vault. Microsoft can't recover the data without the passphrase. [Learn](save-backup-passphrase-securely-in-azure-key-vault.md) how to store a secret in a Key Vault.
 
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