ref-manual: don't refer to poky-lsb

This was removed in 2019, so swap it for poky-altcfg.

(From yocto-docs rev: 9b4c36f7b02dd4bedfec90206744a1e90e37733c)

Signed-off-by: Ross Burton <ross.burton@arm.com>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
(cherry picked from commit 7f7f6570befdda280c174a5f9776b20f53f3ea0d)
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

documentation/ref-manual/features.rst

@@ -12,7 +12,7 @@ Features provide a mechanism for working out which packages should be
 included in the generated images. Distributions can select which
 features they want to support through the :term:`DISTRO_FEATURES` variable,
 which is set or appended to in a distribution's configuration file such
-as ``poky.conf``, ``poky-tiny.conf``, ``poky-lsb.conf`` and so forth.
+as ``poky.conf``, ``poky-tiny.conf``, ``poky-altcfg.conf`` and so forth.
 Machine features are set in the :term:`MACHINE_FEATURES` variable, which is
 set in the machine configuration file and specifies the hardware
 features for a given machine.