tools: kernel-doc: add a see also section at man pages

tools: kernel-doc: add a see also section at man pages

While cross-references are complex, as related ones can be on
different files, we can at least correlate the ones that belong
to the same file, adding a SEE ALSO section for them.

The result is not bad. See for instance:

	$ tools/docs/sphinx-build-wrapper --sphinxdirs driver-api/media -- mandocs
	$ man Documentation/output/driver-api/man/edac_pci_add_device.9

	edac_pci_add_device(9)  Kernel Hacker's Manual  edac_pci_add_device(9)

	NAME
	       edac_pci_add_device  - Insert the 'edac_dev' structure into the
	       edac_pci global list and create sysfs entries  associated  with
	       edac_pci structure.

	SYNOPSIS
	       int  edac_pci_add_device  (struct  edac_pci_ctl_info *pci , int
	       edac_idx );

	ARGUMENTS
	       pci         pointer to the edac_device structure to be added to
	                   the list

	       edac_idx    A unique numeric identifier to be assigned to the

	RETURN
	       0 on Success, or an error code on failure

	SEE ALSO
	       edac_pci_alloc_ctl_info(9),          edac_pci_free_ctl_info(9),
	       edac_pci_alloc_index(9),  edac_pci_del_device(9), edac_pci_cre‐
	       ate_generic_ctl(9),            edac_pci_release_generic_ctl(9),
	       edac_pci_create_sysfs(9), edac_pci_remove_sysfs(9)

	August 2025               edac_pci_add_device   edac_pci_add_device(9)

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Message-ID: <fba25efb41eadad17a54e6275a6191173d702f00.1758196090.git.mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>