[PATCH 2/3] docs: avoid unreferenced footnote

[Paolo Bonzini <pbonzini@redhat.com>]

The link to fosdem.org is inlined but also included in the footnote [#c].
Replace the inline link with a reference to the footnote, because Sphinx
8.1.0 is a lot stricter about unreferenced footnotes.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 docs/devel/testing/acpi-bits.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/devel/testing/acpi-bits.rst b/docs/devel/testing/acpi-bits.rst
index 78aeb6aa3c4..2e4f1d23def 100644
--- a/docs/devel/testing/acpi-bits.rst
+++ b/docs/devel/testing/acpi-bits.rst
@@ -37,8 +37,8 @@ dependent submodules `here <https://gitlab.com/qemu-project/biosbits-bits>`__.
 This fork contains numerous fixes, a newer acpica and changes specific to
 running these functional QEMU tests using bits. The author of this document
 is the sole maintainer of the QEMU fork of bios bits repository. For more
-information, please see author's `FOSDEM talk on this bios-bits based test
-framework <https://fosdem.org/2024/schedule/event/fosdem-2024-2262-exercising-qemu-generated-acpi-smbios-tables-using-biosbits-from-within-a-guest-vm-/>`__.
+information, please see author's FOSDEM talk on this bios-bits based test
+framework\ [#c]_.
 
 *********************************
 Description of the test framework
-- 
2.46.2