ref-manual: Describe grub-efi-cfg overrides and GRUB_TITLE

This patch describes how to use overrides for grub-efi-cfg because that
is otherwise only clear after reading the .bbclass file. It also adds
a description for GRUB_TITLE.

(From yocto-docs rev: b9ec7d124c9cbaf6c05415277fa028a39ce9e02f)

Signed-off-by: "Simon A. Eugster" <simon.eu@gmail.com>
Reviewed-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 86023195d3..adbef69d8f 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -3382,6 +3382,11 @@ system and gives an overview of their function and contents.
       :ref:`ref-classes-grub-efi` class for more information
       on how this variable is used.
 
+   :term:`GRUB_TITLE`
+      Specifies custom titles for GRUB labels defined in  :term:`LABELS`. See
+      the :ref:`ref-classes-grub-efi` class for more information on how this
+      variable is used.
+
    :term:`GTKIMMODULES_PACKAGES`
       When inheriting the :ref:`ref-classes-gtk-immodules-cache` class,
       this variable specifies the packages that contain the GTK+ input