Help: Fix build_command alternative signature docs

Do not specify that --config will not be added, because the
command does add it.

Help/command/build_command.rst

@@ -32,7 +32,7 @@ This second signature is deprecated, but still available for backwards
 compatibility.  Use the first signature instead.
 
 It sets the given ``<cachevariable>`` to a command-line string as
-above but without the ``--config`` or ``--target`` options.
+above but without the ``--target`` option.
 The ``<makecommand>`` is ignored but should be the full path to
 msdev, devenv, nmake, make or one of the end user build tools
 for legacy invocations.