tree-wide: make the :doc: directive use absolute paths

This makes all :doc: directives use an absolute paths (with the root
directory being documentation/ in the repo).

This is then consistent across the whole source and is easier to review
and move files around, you just need to know where a file is located
relative to documentation/ directory and use that.

This gets rid of paths looking in parent directory with '..' as well as
expecting a file to be in the same directory as the other file it points
to via the :doc: directive.

(From yocto-docs rev: b9457f2005b0bea49c54e9727eb30e9458084886)

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/bsp-guide/bsp.rst

@@ -881,7 +881,7 @@ The requirements for a released BSP that conform to the Yocto Project are:
    ``recipes-*`` subdirectories specific to the recipe's function, or
    within a subdirectory containing a set of closely-related recipes.
    The recipes themselves should follow the general guidelines for
-   recipes found in the ":doc:`../contributor-guide/recipe-style-guide`"
+   recipes found in the ":doc:`/contributor-guide/recipe-style-guide`"
    in the Yocto Project and OpenEmbedded Contributor Guide.
 
 -  *License File:* You must include a license file in the
@@ -915,7 +915,7 @@ The requirements for a released BSP that conform to the Yocto Project are:
    -  The name and contact information for the BSP layer maintainer.
       This is the person to whom patches and questions should be sent.
       For information on how to find the right person, see the
-      :doc:`../contributor-guide/submit-changes` section in the Yocto Project and
+      :doc:`/contributor-guide/submit-changes` section in the Yocto Project and
       OpenEmbedded Contributor Guide.
 
    -  Instructions on how to build the BSP using the BSP layer.