documentation/conf.py: define a manpage url

By defining the manpages_url we can use the :manpage: role in the
documentation for providing links to manpages. See:
https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-manpages_url

Replace existing manpages links to use this role.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
(From yocto-docs rev: 0d0115cb2d96960837678f775cf5c2297494c51c)

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
(cherry picked from commit 4e63cd74cd1a330ea5e96bb04243a90f607b2857)
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/conf.py

@@ -111,6 +111,9 @@ extlinks = {
     'wikipedia': ('https://en.wikipedia.org/wiki/%s', None),
 }
 
+# To be able to use :manpage:`<something>` in the docs.
+manpages_url = 'https://manpages.debian.org/{path}'
+
 # Intersphinx config to use cross reference with BitBake user manual
 intersphinx_mapping = {
     'bitbake': ('https://docs.yoctoproject.org/bitbake/' + bitbake_version, None)

documentation/overview-manual/concepts.rst

@@ -2204,7 +2204,7 @@ require root privileges, the fact that some earlier steps ran in a fake
 root environment does not cause problems.
 
 The capability to run tasks in a fake root environment is known as
-"`fakeroot <http://man.he.net/man1/fakeroot>`__", which is derived from
+":manpage:`fakeroot <fakeroot(1)>`", which is derived from
 the BitBake keyword/variable flag that requests a fake root environment
 for a task.
 

documentation/overview-manual/yp-intro.rst

@@ -400,7 +400,7 @@ Yocto Project:
    Autobuilder :doc:`here </test-manual/understand-autobuilder>`.
 
 -  *Pseudo:* Pseudo is the Yocto Project implementation of
-   `fakeroot <http://man.he.net/man1/fakeroot>`__, which is used to run
+   :manpage:`fakeroot <fakeroot(1)>`, which is used to run
    commands in an environment that seemingly has root privileges.
 
    During a build, it can be necessary to perform operations that

documentation/ref-manual/variables.rst

@@ -4539,8 +4539,7 @@ system and gives an overview of their function and contents.
 
       The value in :term:`INITSCRIPT_PARAMS` is passed through to the
       ``update-rc.d`` command. For more information on valid parameters,
-      please see the ``update-rc.d`` manual page at
-      https://manpages.debian.org/buster/init-system-helpers/update-rc.d.8.en.html
+      please see the manual page: :manpage:`update-rc.d <update-rc.d(8)>`.
 
    :term:`INSANE_SKIP`
       Specifies the QA checks to skip for a specific package within a