Added missing period

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cc: @msmbaldwin

Author: MarileeTurscak-MSFT

articles/key-vault/general/overview-security.md

@@ -38,7 +38,7 @@ The model of a single mechanism for authentication to both planes has several be
 
 - Organizations can control access centrally to all key vaults in their organization.
 - If a user leaves, they instantly lose access to all key vaults in the organization.
-- Organizations can customize authentication by using the options in Azure AD, such as to enable multi-factor authentication for added security
+- Organizations can customize authentication by using the options in Azure AD, such as to enable multi-factor authentication for added security.
 
 ### Managing administrative access to Key Vault