Fix typo

Change-Id: I9fdd5e25dff09593dec3947de4c5a916a15f48a1
Reviewed-on: https://gerrit.libreoffice.org/72389Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
Tested-by: Julien Nabet <serval2412@yahoo.fr>

offapi/com/sun/star/security/ExtAltNameType.idl

@@ -39,7 +39,7 @@ enum ExtAltNameType
 
     /**
      * The entry contains rfc822 name.
-     * The value of CertAltNameEntry contains a OUString.
+     * The value of CertAltNameEntry contains an OUString.
      *
      * @see com::sun::star::security::CertAltNameEntry
      */