docs: translations: it: avoid duplicate refs at programming-language.rst

As the translations document is part of the main body, we can't
keep duplicated references there. So, prefix the Italian ones
with "it-".

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/e733111f3599dff96524ad09ace5204ac6bb496b.1583250595.git.mchehab+huawei@kernel.org


Signed-off-by: Jonathan Corbet <corbet@lwn.net>