qemu-block-drivers.rst.inc is embedded twice
Description of problem:
`qemu-block-drivers.rst.inc` is included both in `docs/system/qemu-block-drivers.rst` and in `docs/system/images.rst`, so it is repeated both at https://www.qemu.org/docs/master/system/qemu-block-drivers.html and at https://www.qemu.org/docs/master/system/images.html .

This also makes the generation of the sphinx `objects.inv` search index nondeterministic: it will point to one page or the other depending on random chance at build time.

Perhaps instead of embedding the drivers, `images.rst` should point to https://www.qemu.org/docs/master/system/qemu-block-drivers.html for the list?