docs: fix internal references

It seems last time I tried to fix these, I missed a few spots. So let's
try to get things right this time.

Fixes: 429ff054917 ("docs/relnotes: update internal references")
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5671>
4 files changed