Clarify the server_address as used in ConnectionItem class (#1659)

Clarify the server_address as used in ConnectionItem class (as contrasted with how it's used in the Server class)

Author: bcantoni

docs/api-ref.md

@@ -227,10 +227,10 @@ Name   |  Description
 `datasource_name` |  The name of the data source.
 `id`  |  The identifier of the connection.
 `connection_type`  |  The type of connection.
-`username`     | The username for the connection. (see ConnectionCredentials)
-`password`  |  The password used for the connection. (see ConnectionCredentials)
-`embed_password`  |  (Boolean) Determines whether to embed the password (`True`) for the workbook or data source connection or not (`False`). (see ConnectionCredentials)
-`server_address`   |  The server address for the connection.
+`username`     | The username for the connection (see ConnectionCredentials).
+`password`  |  The password used for the connection (see ConnectionCredentials).
+`embed_password`  |  (Boolean) Determines whether to embed the password (`True`) for the workbook or data source connection or not (`False`) (see ConnectionCredentials).
+`server_address`   |  The server address for the connection (host name for the Tableau Server).
 `server_port`   |  The port used for the connection.
 `connection_credentials` | The Connection Credentials object containing authentication details for the connection. Replaces username/password/embed_password when publishing a flow, document or workbook file in the request body.