add sqlsrv driver to configuration documentation

docs/en/reference/configuration.rst

@@ -51,6 +51,8 @@ interfaces to use. It can be configured in one of three ways:
       extension.
       **Note that this driver caused problems in our tests. Prefer the oci8 driver if possible.**
    -  ``pdo_sqlsrv``: A Microsoft SQL Server driver that uses pdo\_sqlsrv PDO
+      **Note that this driver caused problems in our tests. Prefer the sqlsrv driver if possible.**
+   -  ``sqlsrv``: A Microsoft SQL Server driver that uses the sqlsrv PHP extension.
    -  ``oci8``: An Oracle driver that uses the oci8 PHP extension.
    -  ``sqlanywhere``: A SAP Sybase SQL Anywhere driver that uses the sqlanywhere PHP extension.
 
@@ -192,8 +194,8 @@ pdo\_oci / oci8
 -  ``charset`` (string): The charset used when connecting to the
    database.
 
-pdo\_sqlsrv
-^^^^^^^^^^^
+pdo\_sqlsrv / sqlsrv
+^^^^^^^^^^^^^^^^^^^^
 
 
 -  ``user`` (string): Username to use when connecting to the